U.S. patent application number 17/673017 was filed with the patent office on 2022-08-18 for zoom lens system, and image capture device and interchangeable lens unit including the zoom lens system.
The applicant listed for this patent is Panasonic Intellectual Property Management Co., Ltd.. Invention is credited to Takakazu BITO, Kunio DOHNO, Takahiro KITADA, Yoshio MATSUMURA, Takehiro NISHIOKA.
Application Number | 20220260814 17/673017 |
Document ID | / |
Family ID | 1000006169763 |
Filed Date | 2022-08-18 |
United States Patent
Application |
20220260814 |
Kind Code |
A1 |
KITADA; Takahiro ; et
al. |
August 18, 2022 |
ZOOM LENS SYSTEM, AND IMAGE CAPTURE DEVICE AND INTERCHANGEABLE LENS
UNIT INCLUDING THE ZOOM LENS SYSTEM
Abstract
A zoom lens system includes at least six lens groups, each of
which has power. An interval between each pair of lens groups that
are adjacent to each other among the at least six lens groups
changes while the zoom lens system is zooming. Each of three lens
groups, which are respectively located closest, second closest, and
third closest to an image plane, out of the at least six lens
groups consists of one or more bonded lenses.
Inventors: |
KITADA; Takahiro; (Osaka,
JP) ; NISHIOKA; Takehiro; (Nara, JP) ;
MATSUMURA; Yoshio; (Osaka, JP) ; BITO; Takakazu;
(Osaka, JP) ; DOHNO; Kunio; (Osaka, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Panasonic Intellectual Property Management Co., Ltd. |
Osaka |
|
JP |
|
|
Family ID: |
1000006169763 |
Appl. No.: |
17/673017 |
Filed: |
February 16, 2022 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G02B 7/10 20130101; G02B
15/1461 20190801; G02B 7/14 20130101 |
International
Class: |
G02B 15/14 20060101
G02B015/14; G02B 7/14 20060101 G02B007/14; G02B 7/10 20060101
G02B007/10 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 17, 2021 |
JP |
2021-023038 |
Feb 17, 2021 |
JP |
2021-023041 |
Claims
1. A zoom lens system comprising at least six lens groups, each of
the at least six lens groups having power, an interval between each
pair of lens groups that are adjacent to each other among the at
least six lens groups changing while the zoom lens system is
zooming, each of three lens groups, which are respectively located
closest, second closest, and third closest to an image plane, out
of the at least six lens groups consisting of one or more bonded
lenses.
2. The zoom lens system of claim 1, wherein another lens group,
which is located fourth closest to the image plane, out of the at
least six lens groups also consists of one or more bonded
lenses.
3. The zoom lens system of claim 1, wherein each of the three lens
groups consists of a single bonded lens.
4. The zoom lens system of claim 1, wherein a second lens group,
which is located second closest to an object, out of the at least
six lens groups does not move while the zoom lens system is
zooming.
5. The zoom lens system of claim 1, wherein an N.sup.th lens group,
which is located closer to the image plane than any other lens
group of the at least six lens groups, includes a negative lens
GNLn, and the zoom lens system satisfies a condition expressed by
the following inequality: -0.3<fGNLn/LW<0 where fGNLn is a
focal length of the negative lens GNLn and LW is a total lens
length at a wide-angle end.
6. The zoom lens system of claim 1, wherein the zoom lens system
satisfies a condition expressed by the following inequality:
0.3<R_GN.sub.c/fG.sub.N<0.7 where R_GN.sub.c is a radius of
curvature of a bonded face of a bonded lens that forms part of an
N.sup.th lens group located closer to the image plane than any
other lens group of the at least six lens groups, and fG.sub.N is a
focal length of the N.sup.th lens group.
7. The zoom lens system of claim 1, wherein when a lens group
located closer to the image plane than any other lens group of the
at least six lens groups is called an N.sup.th lens group, another
lens group located adjacent to, and closer to an object than, the
N.sup.th lens group is called an (N-1.sup.th lens group, and still
another lens group located adjacent to, and closer to the object
than, the (N-1.sup.th lens group is called an (N-2).sup.th lens
group, while the zoom lens system is focusing to make a transition
from an infinity in-focus state toward a close-object in-focus
state, at least the (N-2.sup.th lens group moves along an optical
axis of the zoom lens system, and the zoom lens system satisfies a
condition expressed by the following inequality:
-1.5<fG.sub.N-1/fG.sub.N<-0.5 where fG.sub.N-1 is a focal
length of the (N-1).sup.th lens group and fG.sub.N is a focal
length of the N.sup.th lens group.
8. The zoom lens system of claim 1, wherein when a negative lens,
having the largest refractive index with respect to a d-line out of
at least one negative lens that forms a third lens group, which is
located third closest to an object out of the at least six lens
groups, is a negative lens LG3n, the zoom lens system satisfies a
condition expressed by the following inequality, nLG3n>1.95
where nLG3n is a refractive index of the negative lens LG3n with
respect to the d-line.
9. The zoom lens system of claim 1, wherein when a negative lens,
having the smallest Abbe number with respect to a d-line out of at
least one negative lens that forms a third lens group, which is
located third closest to an object out of the at least six lens
groups, is a negative lens LG3n, the zoom lens system satisfies a
condition expressed by the following inequality, vLG3n<35.0
where vLG3n is an Abbe number of the negative lens LG3n with
respect to the d-line.
10. The zoom lens system of claim 1, wherein the zoom lens system
satisfies a condition expressed by the following inequality:
0.2<fT/LT<1.5 where fT is a focal length at a telephoto end
and LT is a total lens length at the telephoto end.
11. The zoom lens system of claim 1, wherein the zoom lens system
satisfies a condition expressed by the following inequality:
0.50<fT/LDT<1.85 where fT is a focal length at a telephoto
end and LDT is a distance measured at the telephoto end along an
optical axis of the zoom lens system from an object-side surface of
a lens located closer to the object than any other lens of the zoom
lens system to an image-side surface of a lens located closer to
the image plane than any other lens of the zoom lens system.
12. An image capture device configured to transform an optical
image of an object into an electrical image signal and output the
electrical image signal thus transformed, the image capture device
comprising: a zoom lens system configured to form the optical image
of the object; and an image sensor configured to transform the
optical image formed by the zoom lens system into the electrical
image signal, the zoom lens system comprising at least six lens
groups, each of the at least six lens groups having power, an
interval between each pair of lens groups that are adjacent to each
other among the at least six lens groups changing while the zoom
lens system is zooming, each of three lens groups, which are
respectively located closest, second closest, and third closest to
an image plane, out of the at least six lens groups consisting of
one or more bonded lenses.
13. An interchangeable lens unit configured to be removably
connected, via a mount, to a camera body, the camera body
including: an image sensor configured to receive an optical image
and transform the optical image into an electrical image signal;
and the mount, the interchangeable lens unit comprising at least
six lens groups, each of the at least six lens groups having power,
an interval between each pair of lens groups that are adjacent to
each other among the at least six lens groups changing while the
interchangeable lens unit is zooming, each of three lens groups,
which are respectively located closest, second closest, and third
closest to an image plane, out of the at least six lens groups
consisting of one or more bonded lenses.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The present application is based upon, and claims the
benefit of priority to, Japanese Patent Application No. 2021-023038
filed on Feb. 17, 2021, and Japanese Patent Application No.
2021-023041 filed on Feb. 17, 2021, the entire disclosures of which
are hereby incorporated by reference.
TECHNICAL FIELD
[0002] The present disclosure relates to a zoom lens system
including at least six lens groups, and also relates to an image
capture device and interchangeable lens system including such a
zoom lens system.
BACKGROUND ART
[0003] JP 2019-020679 A discloses a zoom lens system including: a
first lens group having positive refractive power; a second lens
group having negative refractive power; a third lens group having
positive refractive power; a fourth lens group having positive
refractive power; a fifth lens group having negative refractive
power, a sixth lens group having positive refractive power, and a
seventh lens group having negative refractive power, where these
first through seventh lens groups are arranged in this order such
that the first lens group is located closer to an object than any
other lens group is and that the seventh lens group is located
closer to an image plane than any other lens group is.
SUMMARY
[0004] The present disclosure provides a zoom lens system in which
various types of aberrations have been compensated for sufficiently
over the entire zoom range, and also provides an image capture
device and interchangeable lens system including such a zoom lens
system.
[0005] A zoom lens system according to an aspect of the present
disclosure includes at least six lens groups, each of which has
power. An interval between each pair of lens groups that are
adjacent to each other among the at least six lens groups changes
while the zoom lens system is zooming. Each of three lens groups,
which are respectively located closest, second closest, and third
closest to an image plane, out of the at least six lens groups
consists of one or more bonded lenses.
[0006] An image capture device according to another aspect of the
present disclosure may transform an optical image of an object into
an electrical image signal and output the electrical image signal
thus transformed. The image capture device includes: a zoom lens
system to form the optical image of the object; and an image sensor
to transform the optical image formed by the zoom lens system into
the electrical image signal. The zoom lens system includes at least
six lens groups, each of which has power. An interval between each
pair of lens groups that are adjacent to each other among the at
least six lens groups changes while the zoom lens system is
zooming. Each of three lens groups, which are respectively located
closest, second closest, and third closest to an image plane, out
of the at least six lens groups consists of one or more bonded
lenses.
[0007] An interchangeable lens unit according to still another
aspect of the present disclosure is removably connected, via a
mount, to a camera body. The camera body includes: an image sensor
to receive an optical image and transform the optical image into an
electrical image signal; and the mount. The interchangeable lens
unit includes at least six lens groups, each of which has power. An
interval between each pair of lens groups that are adjacent to each
other among the at least six lens groups changes while the
interchangeable lens unit is zooming. Each of three lens groups,
which are respectively located closest, second closest, and third
closest to an image plane, out of the at least six lens groups
consists of one or more bonded lenses.
BRIEF DESCRIPTION OF DRAWINGS
[0008] The figures depict one or more implementations in accordance
with the present teaching, by way of example only, not by way of
limitations. In the figures, like reference numerals refer to the
same or similar elements.
[0009] FIG. 1 illustrates lens arrangements showing what state a
zoom lens system according to a first embodiment (corresponding to
a first example of numerical values) assumes at an infinity focus
point;
[0010] FIG. 2 illustrates longitudinal aberration diagrams showing
what state the zoom lens system assumes at the infinity focus point
in the first example of numerical values;
[0011] FIG. 3 illustrates lateral aberration diagrams showing a
basic state where no image blur compensation is performed at the
telephoto end and an image blur compensated state at the telephoto
end in a zoom lens system in the first example of numerical
values;
[0012] FIG. 4 illustrates lens arrangements showing what state a
zoom lens system according to a second embodiment (corresponding to
a second example of numerical values) assumes at an infinity focus
point;
[0013] FIG. 5 illustrates longitudinal aberration diagrams showing
what state the zoom lens system assumes at the infinity focus point
in the second example of numerical values;
[0014] FIG. 6 illustrates lateral aberration diagrams showing a
basic state where no image blur compensation is performed at the
telephoto end and an image blur compensated state at the telephoto
end in a zoom lens system in the second example of numerical
values;
[0015] FIG. 7 illustrates lens arrangements showing what state a
zoom lens system according to a third embodiment (corresponding to
a third example of numerical values) assumes at an infinity focus
point;
[0016] FIG. 8 illustrates longitudinal aberration diagrams showing
what state the zoom lens system assumes at the infinity focus point
in the third example of numerical values;
[0017] FIG. 9 illustrates lateral aberration diagrams showing a
basic state where no image blur compensation is performed at the
telephoto end and an image blur compensated state at the telephoto
end in a zoom lens system in the third example of numerical
values;
[0018] FIG. 10 illustrates lens arrangements showing what state a
zoom lens system according to a fourth embodiment (corresponding to
a fourth example of numerical values) assumes at an infinity focus
point;
[0019] FIG. 11 illustrates longitudinal aberration diagrams showing
what state the zoom lens system assumes at the infinity focus point
in the fourth example of numerical values;
[0020] FIG. 12 illustrates lateral aberration diagrams showing a
basic state where no image blur compensation is performed at the
telephoto end and an image blur compensated state at the telephoto
end in a zoom lens system in the fourth example of numerical
values;
[0021] FIG. 13 illustrates lens arrangements showing what state a
zoom lens system according to a fifth embodiment (corresponding to
a fifth example of numerical values) assumes at an infinity focus
point;
[0022] FIG. 14 illustrates longitudinal aberration diagrams showing
what state the zoom lens system assumes at the infinity focus point
in the fifth example of numerical values;
[0023] FIG. 15 illustrates lateral aberration diagrams showing a
basic state where no image blur compensation is performed at the
telephoto end and an image blur compensated state at the telephoto
end in a zoom lens system in the fifth example of numerical
values;
[0024] FIG. 16 illustrates a schematic configuration for an image
capture device according to the first embodiment; and
[0025] FIG. 17 illustrates a schematic configuration for a camera
system according to the first embodiment.
DETAILED DESCRIPTION
[0026] Embodiments of the present disclosure will now be described
in detail with reference to the accompanying drawings as
appropriate. Note that unnecessarily detailed description may be
omitted. For example, detailed description of already well-known
matters and redundant description of substantially the same
configuration may be omitted. This is done to avoid making the
following description overly redundant and thereby to help one of
ordinary skill in the art understand the present disclosure
easily.
[0027] In addition, note that the accompanying drawings and the
following description are provided to help one of ordinary skill in
the art understand the present disclosure fully and should not be
construed as limiting the scope of the present disclosure, which is
defined by the appended claims.
First to Fifth Embodiments
[0028] A zoom lens system according to each of first to fifth
embodiments to be described below achieves improved optical
performance over the entire zoom range. Next, zoom lens systems
according to the first to fifth embodiments will be described one
by one with reference to the accompanying drawings.
[0029] FIGS. 1, 4, 7, 10, and 13 illustrate lens arrangement
diagrams according to first, second, third, fourth, and fifth
embodiments, respectively, each showing what state a zoom lens
system assumes at an infinity in-focus point.
[0030] In FIGS. 1, 4, 7, 10, and 13, portion (a) illustrates a lens
arrangement at the wide-angle end (which is a state with the
shortest focal length fW); portion (d) illustrates a lens
arrangement at a middle position (which is a state with a middle
focal length fM= (fW*fT)); and portion (e) illustrates a lens
arrangement at the telephoto end (which is a state with the longest
focal length fT). Note that portions (a), (d), and (e) of FIGS. 1,
4, 7, 10, and 13 have the same aspect ratio.
[0031] Furthermore, in portion (a) of FIGS. 1, 4, 7, 10, and 13,
the asterisk (*) attached to a surface of a particular lens
indicates that the surface is an aspheric surface. Note that in the
lenses, a surface with no asterisks is a spherical surface.
[0032] In the following description, a "positive lens" herein
refers to a lens having positive power and a "negative lens" herein
refers to a lens having negative power.
[0033] Also, in FIGS. 1, 4, 7, 10, and 13, the polygon arrows shown
between portion (c) thereof each connect together the respective
positions of the lens groups at the wide-angle end (Wide), middle
position (Mid), and telephoto end (Tele) from top to bottom. Note
that these polygon arrows just connect the wide-angle end to the
middle position and the middle position to the telephoto end with
the curves, and do not indicate the actual movement of the lens
groups.
[0034] In each of the plurality of lens groups, a plurality of
lenses included in the lens group move together. For example, the
first to fourth lenses L1-L4 included in the first lens group G1
move together.
[0035] Furthermore, in portion (b) of FIGS. 1, 4, 7, 10, and 13,
the respective lens groups are designated by the reference signs
G1-G6 or G1-G7 corresponding to their respective positions shown in
portion (a).
[0036] Furthermore, the signs (+) and (-) added to the reference
signs of the respective lens groups in portion (b) of FIGS. 1, 4,
7, 10, and 13 indicate the powers of the respective lens groups
G1-G6 or G1-G7. That is to say, the positive sign (+) indicates
positive power, and the negative sign (-) indicates negative
power.
[0037] Also, the arrows added to the lens groups in portion (b) of
FIGS. 1, 4, 7, 10, and 13 each indicate the direction of movement
while the zoom lens system is focusing to make a transition from
the infinity in-focus state toward the close-object in-focus state.
Note that in FIGS. 1, 4, 7, 10, and 13, the reference signs of
respective lens groups are shown under the respective lens groups
in portion (a) thereof, and therefore, an arrow indicating focusing
is shown under the sign of each lens group for convenience's sake.
The directions of movement of the respective lens groups during
focusing will be described more specifically later with respect to
each of the first through fifth embodiments.
[0038] Furthermore, in portions (a), (d), and (e) of FIGS. 1, 4, 7,
10, and 13, the straight line drawn at the right end indicates the
position of the image plane S (i.e., a surface, facing the object,
of the image sensor). Therefore, the left end of the drawings
corresponds to the object side. Furthermore, a parallel plate such
as a low-pass filter or cover glass is disposed between the lens
group on the last stage facing the image plane S and the image
plane S.
First Embodiment
[0039] FIG. 1 illustrates a zoom lens system according to a first
embodiment.
[0040] The zoom lens system includes: a first lens group G1 having
positive power; a second lens group G2 having negative power; a
third lens group G3 having positive power; a fourth lens group G4
having positive power; a fifth lens group G5 having negative power;
a sixth lens group G6 having positive power; and a seventh lens
group G7 having negative power. The first, second, third, fourth,
fifth, sixth, and seventh lens groups G1-G7 are arranged in this
order such that the first lens group G1 is located closer to an
object than any other lens group is and that the seventh lens group
G7 is located closer to an image plane than any other lens group
is.
[0041] The zoom lens system forms an image at a point on the image
plane S.
[0042] The third through seventh lens groups G3-G7 form an
exemplary rear group GR.
[0043] The fifth lens group G5 is an example of the (N-2).sup.th
lens group. The sixth lens group G6 is an example of the
(N-1).sup.th lens group. The seventh lens group G7 is an example of
the N.sup.th lens group. Note that N is an algebraic number
representing the number of lens groups included in the zoom lens
system.
[0044] The first lens group G1 is made up of: a first lens L1
having negative power; a second lens L2 having positive power; and
a third lens L3 having positive power The first lens L1, the second
lens L2, and the third lens L3 are arranged in this order such that
the first lens L1 is located closer to the object than any other
member of this first lens group G1 and that the third lens L3 is
located closer to the image plane than any other member of this
first lens group G1. In this case, the first lens L1 is an example
of the negative lens G1L1, the second lens L2 is an example of the
positive lens G1L2, and the third lens L3 is an example of the
positive lens G1L3.
[0045] The second lens group G2 is made up of: a fourth lens L4
having negative power; a fifth lens L5 having negative power; and a
sixth lens L6 having positive power. The fourth lens L4, the fifth
lens L5, and the sixth lens L6 are arranged in this order such that
the fourth lens L4 is located closer to the object than any other
member of this second lens group G2 and that the sixth lens L6 is
located closer to the image plane than any other member of this
second lens group G2. The fifth lens L5 and the sixth lens L6 are
bonded together with an adhesive, for example, to form a bonded
lens. That is to say, a single bonded lens is formed by the fifth
lens L5 and the sixth lens L6.
[0046] The third lens group G3 is made up of: a seventh lens L7
having positive power; an eighth lens L8 having positive power; a
ninth lens L9 having negative power; and an aperture stop A. The
seventh lens L7, the eighth lens L8, the ninth lens L9, and the
aperture stop A are arranged in this order such that the seventh
lens L7 is located closer to the object than any other member of
this third lens group G3 and that the aperture stop A is located
closer to the image plane than any other member of this third lens
group G3. The eighth lens L8 and the ninth lens L9 are bonded
together with an adhesive, for example, to form a bonded lens.
[0047] The fourth lens group G4 is made up of: a tenth lens L10
having negative power; and an eleventh lens L11 having positive
power. The tenth lens L10 and the eleventh lens L11 are arranged in
this order such that the tenth lens L10 is located closer to the
object than the eleventh lens L11 and that the eleventh lens L11 is
located closer to the image plane than the tenth lens L10. The
tenth lens L10 and the eleventh lens L11 are bonded together with
an adhesive, for example, to form a bonded lens.
[0048] The fifth lens group G5 is made up of: a twelfth lens L12
having positive power; and a thirteenth lens L13 having negative
power. The twelfth lens L12 and the thirteenth lens L13 are
arranged in this order such that the twelfth lens L12 is located
closer to the object than the thirteenth lens L13 and that the
thirteenth lens L13 is located closer to the image plane than the
twelfth lens L12. The twelfth lens L12 and the thirteenth lens L13
are bonded together with an adhesive, for example, to form a bonded
lens.
[0049] The sixth lens group G6 is made up of: a fourteenth lens L14
having positive power; and a fifteenth lens L15 having negative
power. The fourteenth lens L14 and the fifteenth lens L15 are
arranged in this order such that the fourteenth lens L14 is located
closer to the object than the fifteenth lens L15 and that the
fifteenth lens L15 is located closer to the image plane than the
fourteenth lens L14. The fourteenth lens L14 and the fifteenth lens
L15 are bonded together with an adhesive, for example, to form a
bonded lens.
[0050] The seventh lens group G7 is made up of: a sixteenth lens
L16 having positive power; and a seventeenth lens L17 having
negative power. The sixteenth lens L16 and the seventeenth lens L17
are arranged in this order such that the sixteenth lens L16 is
located closer to the object than the seventeenth lens L17 and that
the seventeenth lens L17 is located closer to the image plane than
the sixteenth lens L16. The sixteenth lens L16 and the seventeenth
lens L17 are bonded together with an adhesive, for example, to form
a bonded lens.
[0051] The respective lenses will be described.
[0052] First, the respective lenses that form the first lens group
G1 will be described. The first lens L1 is a meniscus lens having a
convex surface facing the object. The second lens L2 is a biconvex
lens. The third lens L3 is a meniscus lens having a convex surface
facing the object.
[0053] Next, the respective lenses that form the second lens group
G2 will be described. The fourth lens L4 is a biconcave lens. The
fifth lens L5 is a meniscus lens having a convex surface facing the
object. The sixth lens L6 is a meniscus lens having a convex
surface facing the object.
[0054] Next, the respective lenses that form the third lens group
G3 will be described. The seventh lens L7 is a biconvex lens. The
eighth lens L8 is a biconvex lens. The ninth lens L9 is a biconcave
lens. In this case, the eighth lens L8 is an example of the
positive lens LG3p. The ninth lens L9 is an example of the negative
lens LG3n.
[0055] Next, the respective lenses that form the fourth lens group
G4 will be described. The tenth lens L10 is a biconcave lens. The
eleventh lens L11 is a biconvex lens.
[0056] Next, the respective lenses that form the fifth lens group
G5 will be described. The twelfth lens L12 is a biconvex lens. The
thirteenth lens L13 is a biconcave lens.
[0057] Next, the respective lenses that form the sixth lens group
G6 will be described. The fourteenth lens L14 is a biconvex lens.
The fifteenth lens L15 is a meniscus lens having a convex surface
facing the image.
[0058] Next, the respective lenses that form the seventh lens group
G7 will be described. The sixteenth lens L16 is a meniscus lens
having a convex surface facing the image. The seventeenth lens L17
is a biconcave lens. In this case, the seventeenth lens L17 is an
example of the negative lens GNLn.
[0059] While the zoom lens system according to the first embodiment
is zooming from the wide-angle end toward the telephoto end during
a shooting session, the first lens group G1, the third lens group
G3, the fourth lens group G4, the fifth lens group G5, the sixth
lens group G6, and the seventh lens group G7 move toward the object
with respect to the image plane S. On the other hand, the second
lens group G2 is fixed while the zoom lens system is zooming from
the wide-angle end toward the telephoto end during the shooting
session. In addition, as the zoom lens system is zooming, the
respective lens groups move along the optical axis such that the
interval between the first lens group G1 and the second lens group
G2 increases, the interval between the second lens group G2 and the
third lens group G3 decreases, the interval between the third lens
group G3 and the fourth lens group G4 decreases, the interval
between the fourth lens group G4 and the fifth lens group G5
increases from the wide-angle end through the middle position and
decreases from the middle position through the telephoto end, the
interval between the fifth lens group G5 and the sixth lens group
G6 increases, and the interval between the sixth lens group G6 and
the seventh lens group G7 decreases.
[0060] While the zoom lens system according to the first embodiment
is focusing to make a transition from the infinity in-focus state
toward the close-object in-focus state, the fifth lens group G5
moves along the optical axis toward the image plane.
[0061] Note that every lens (image blur compensation lens)
belonging to the second lens group G2 moves perpendicularly to the
optical axis to make optical compensation for image blur. This
image blur compensation lens allows the zoom lens system to make
compensation for the movement of an image point due to the
vibration of the entire system. That is to say, this allows the
zoom lens system to make optical compensation for an image blur
caused by a camera shake or vibrations, for example.
Second Embodiment
[0062] FIG. 4 illustrates a zoom lens system according to a second
embodiment.
[0063] The zoom lens system includes: a first lens group G1 having
positive power; a second lens group G2 having negative power; a
third lens group G3 having positive power; a fourth lens group G4
having positive power; a fifth lens group G5 having negative power;
a sixth lens group G6 having positive power; and a seventh lens
group G7 having negative power. The first, second, third, fourth,
fifth, sixth, and seventh lens groups G1-G7 are arranged in this
order such that the first lens group G1 is located closer to an
object than any other lens group is and that the seventh lens group
G7 is located closer to an image plane than any other lens group
is.
[0064] The zoom lens system forms an image at a point on the image
plane S.
[0065] The third through seventh lens groups G3-G7 form an
exemplary rear group GR.
[0066] The fifth lens group G5 is an example of the (N-2).sup.th
lens group. The sixth lens group G6 is an example of the
(N-1).sup.th lens group. The seventh lens group G7 is an example of
the N.sup.th lens group.
[0067] The first lens group G1 is made up of: a first lens L1
having negative power; a second lens L2 having positive power; and
a third lens L3 having positive power. The first lens L1, the
second lens L2, and the third lens L3 are arranged in this order
such that the first lens L1 is located closer to the object than
any other member of this first lens group G1 and that the third
lens L3 is located closer to the image plane than any other member
of this first lens group G1. In this case, the first lens L1 is an
example of the negative lens G1L1, the second lens L2 is an example
of the positive lens G1L2, and the third lens L3 is an example of
the positive lens G1L3.
[0068] The second lens group G2 is made up of: a fourth lens L4
having negative power; a fifth lens L5 having negative power; and a
sixth lens L6 having positive power. The fourth lens L4, the fifth
lens L5, and the sixth lens L6 are arranged in this order such that
the fourth lens L4 is located closer to the object than any other
member of this second lens group G2 and that the sixth lens L6 is
located closer to the image plane than any other member of this
second lens group G2. The fifth lens L5 and the sixth lens L6 are
bonded together with an adhesive, for example, to form a bonded
lens.
[0069] The third lens group G3 is made up of: a seventh lens L7
having positive power; an eighth lens L8 having positive power; a
ninth lens L9 having negative power; and an aperture stop A. The
seventh lens L7, the eighth lens L8, the ninth lens L9, and the
aperture stop A are arranged in this order such that the seventh
lens L7 is located closer to the object than any other member of
this third lens group G3 and that the aperture stop A is located
closer to the image plane than any other member of this third lens
group G3. The eighth lens L8 and the ninth lens L9 are bonded
together with an adhesive, for example, to form a bonded lens.
[0070] The fourth lens group G4 is made up of: a tenth lens L10
having negative power; and an eleventh lens L11 having positive
power. The tenth lens L10 and the eleventh lens L11 are arranged in
this order such that the tenth lens L10 is located closer to the
object than the eleventh lens L11 and that the eleventh lens L11 is
located closer to the image plane than the tenth lens L10. The
tenth lens L10 and the eleventh lens L11 are bonded together with
an adhesive, for example, to form a bonded lens.
[0071] The fifth lens group G5 is made up of: a twelfth lens L12
having positive power; and a thirteenth lens L13 having negative
power. The twelfth lens L12 and the thirteenth lens L13 are
arranged in this order such that the twelfth lens L12 is located
closer to the object than the thirteenth lens L13 and that the
thirteenth lens L13 is located closer to the image plane than the
twelfth lens L12. The twelfth lens L12 and the thirteenth lens L13
are bonded together with an adhesive, for example, to form a bonded
lens.
[0072] The sixth lens group G6 is made up of: a fourteenth lens L14
having positive power; and a fifteenth lens L15 having negative
power. The fourteenth lens L14 and the fifteenth lens L15 are
arranged in this order such that the fourteenth lens L14 is located
closer to the object than the fifteenth lens L15 and that the
fifteenth lens L15 is located closer to the image plane than the
fourteenth lens L14. The fourteenth lens L14 and the fifteenth lens
L15 are bonded together with an adhesive, for example, to form a
bonded lens.
[0073] The seventh lens group G7 is made up of: a sixteenth lens
L16 having positive power; and a seventeenth lens L17 having
negative power. The sixteenth lens L16 and the seventeenth lens L17
are arranged in this order such that the sixteenth lens L16 is
located closer to the object than the seventeenth lens L17 and that
the seventeenth lens L17 is located closer to the image plane than
the sixteenth lens L16. The sixteenth lens L16 and the seventeenth
lens L17 are bonded together with an adhesive, for example, to form
a bonded lens.
[0074] The respective lenses will be described.
[0075] First, the respective lenses that form the first lens group
G1 will be described. The first lens L1 is a meniscus lens having a
convex surface facing the object. The second lens L2 is a biconvex
lens. The third lens L3 is a meniscus lens having a convex surface
facing the object.
[0076] Next, the respective lenses that form the second lens group
G2 will be described. The fourth lens L4 is a biconcave lens. The
fifth lens L5 is a plano-concave lens having a concave surface
facing the image. The sixth lens L6 is a meniscus lens having a
convex surface facing the object.
[0077] Next, the respective lenses that form the third lens group
G3 will be described. The seventh lens L7 is a biconvex lens. The
eighth lens L8 is a biconvex lens. The ninth lens L9 is a biconcave
lens. In this case, the eighth lens L8 is an example of the
positive lens LG3p. The ninth lens L9 is an example of the negative
lens LG3n.
[0078] Next, the respective lenses that form the fourth lens group
G4 will be described. The tenth lens L10 is a biconcave lens. The
eleventh lens L11 is a biconvex lens.
[0079] Next, the respective lenses that form the fifth lens group
G5 will be described. The twelfth lens L12 is a biconvex lens. The
thirteenth lens L13 is a biconcave lens.
[0080] Next, the respective lenses that form the sixth lens group
G6 will be described. The fourteenth lens L14 is a biconvex lens.
The fifteenth lens L15 is a meniscus lens having a convex surface
facing the image.
[0081] Next, the respective lenses that form the seventh lens group
G7 will be described. The sixteenth lens L16 is a meniscus lens
having a convex surface facing the image. The seventeenth lens L17
is a biconcave lens. In this case, the seventeenth lens L17 is an
example of the negative lens GNLn.
[0082] While the zoom lens system according to the second
embodiment is zooming from the wide-angle end toward the telephoto
end during a shooting session, the first lens group G1, the third
lens group G3, the fourth lens group G4, the fifth lens group G5,
the sixth lens group G6, and the seventh lens group G7 move toward
the object with respect to the image plane S. On the other hand,
the second lens group G2 is fixed while the zoom lens system is
zooming from the wide-angle end toward the telephoto end during the
shooting session. In addition, as the zoom lens system is zooming,
the respective lens groups move along the optical axis such that
the interval between the first lens group G1 and the second lens
group G2 increases, the interval between the second lens group G2
and the third lens group G3 decreases, the interval between the
third lens group G3 and the fourth lens group G4 decreases, the
interval between the fourth lens group G4 and the fifth lens group
G5 increases from the wide-angle end through the middle position
and decreases from the middle position through the telephoto end,
the interval between the fifth lens group G5 and the sixth lens
group G6 increases, and the interval between the sixth lens group
G6 and the seventh lens group G7 decreases.
[0083] While the zoom lens system according to the second
embodiment is focusing to make a transition from the infinity
in-focus state toward the close-object in-focus state, the fifth
lens group G5 moves along the optical axis toward the image
plane.
[0084] Note that every lens (image blur compensation lens)
belonging to the second lens group G2 moves perpendicularly to the
optical axis to make optical compensation for image blur. This
image blur compensation lens allows the zoom lens system to make
compensation for the movement of an image point due to the
vibration of the entire system. That is to say, this allows the
zoom lens system to make optical compensation for an image blur
caused by a camera shake or vibrations, for example.
Third Embodiment
[0085] FIG. 7 illustrates a zoom lens system according to a third
embodiment.
[0086] The zoom lens system includes: a first lens group G1 having
positive power; a second lens group G2 having negative power; a
third lens group G3 having positive power; a fourth lens group G4
having negative power; a fifth lens group G5 having positive power;
and a sixth lens group G6 having negative power. The first, second,
third, fourth, fifth, and sixth lens groups G1-G6 are arranged in
this order such that the first lens group G1 is located closer to
an object than any other lens group is and that the sixth lens
group G6 is located closer to an image plane than any other lens
group is.
[0087] The zoom lens system forms an image at a point on the image
plane S.
[0088] The third through sixth lens groups G3-G6 form an exemplary
rear group GR.
[0089] The fourth lens group G4 is an example of the (N-2).sup.th
lens group. The fifth lens group G5 is an example of the
(N-1).sup.th lens group. The sixth lens group G6 is an example of
the N.sup.th lens group.
[0090] The first lens group G1 is made up of: a first lens L1
having negative power; a second lens L2 having positive power; and
a third lens L3 having positive power. The first lens L1, the
second lens L2, and the third lens L3 are arranged in this order
such that the first lens L1 is located closer to the object than
any other member of this first lens group G1 and that the third
lens L3 is located closer to the image plane than any other member
of this first lens group G1. In this case, the first lens L1 is an
example of the negative lens G1L1, the second lens L2 is an example
of the positive lens G1L2, and the third lens L3 is an example of
the positive lens G1L3.
[0091] The second lens group G2 is made up of: a fourth lens L4
having negative power; a fifth lens L5 having negative power; and a
sixth lens L6 having positive power. The fourth lens L4, the fifth
lens L5, and the sixth lens L6 are arranged in this order such that
the fourth lens L4 is located closer to the object than any other
member of this second lens group G2 and that the sixth lens L6 is
located closer to the image plane than any other member of this
second lens group G2. The fifth lens L5 and the sixth lens L6 are
bonded together with an adhesive, for example, to form a bonded
lens.
[0092] The third lens group G3 is made up of: a seventh lens L7
having positive power; an eighth lens L8 having positive power; a
ninth lens L9 having negative power; an aperture stop A; a tenth
lens L10 having negative power; and an eleventh lens L11 having
positive power. The seventh lens L7, the eighth lens L8, the ninth
lens L9, the aperture stop A, the tenth lens L10, and the eleventh
lens L11 are arranged in this order such that the seventh lens L7
is located closer to the object than any other member of this third
lens group G3 and that the eleventh lens L11 is located closer to
the image plane than any other member of this third lens group G3.
The eighth lens L8 and the ninth lens L9 are bonded together with
an adhesive, for example, to form a bonded lens. The tenth lens L10
and the eleventh lens L11 are bonded together with an adhesive, for
example, to form a bonded lens.
[0093] The fourth lens group G4 is made up of: a twelfth lens L12
having positive power; and a thirteenth lens L13 having negative
power. The twelfth lens L12 and the thirteenth lens L13 are
arranged in this order such that the twelfth lens L12 is located
closer to the object than the thirteenth lens L13 and that the
thirteenth lens L13 is located closer to the image plane than the
twelfth lens L12. The twelfth lens L12 and the thirteenth lens L13
are bonded together with an adhesive, for example, to form a bonded
lens.
[0094] The fifth lens group G5 is made up of: a fourteenth lens L14
having positive power; and a fifteenth lens L15 having negative
power. The fourteenth lens L14 and the fifteenth lens L15 are
arranged in this order such that the fourteenth lens L14 is located
closer to the object than the fifteenth lens L15 and that the
fifteenth lens L15 is located closer to the image plane than the
fourteenth lens L14. The fourteenth lens L14 and the fifteenth lens
L15 are bonded together with an adhesive, for example, to form a
bonded lens.
[0095] The sixth lens group G6 is made up of: a sixteenth lens L16
having positive power; and a seventeenth lens L17 having negative
power. The sixteenth lens L16 and the seventeenth lens L17 are
arranged in this order such that the sixteenth lens L16 is located
closer to the object than the seventeenth lens L17 and that the
seventeenth lens L17 is located closer to the image plane than the
sixteenth lens L16. The sixteenth lens L16 and the seventeenth lens
L17 are bonded together with an adhesive, for example, to form a
bonded lens.
[0096] The respective lenses will be described.
[0097] First, the respective lenses that form the first lens group
G1 will be described. The first lens L1 is a meniscus lens having a
convex surface facing the object. The second lens L2 is a biconvex
lens. The third lens L3 is a meniscus lens having a convex surface
facing the object.
[0098] Next, the respective lenses that form the second lens group
G2 will be described. The fourth lens L4 is a biconcave lens. The
fifth lens L5 is a meniscus lens having a convex surface facing the
object. The sixth lens L6 is a meniscus lens having a convex
surface facing the object.
[0099] Next, the respective lenses that form the third lens group
G3 will be described. The seventh lens L7 is a biconvex lens. The
eighth lens L8 is a biconvex lens. The ninth lens L9 is a biconcave
lens. The tenth lens L10 is a meniscus lens having a convex surface
facing the object. The eleventh lens L11 is a biconvex lens. In
this case, the eighth lens L8 is an example of the positive lens
LG3p. The ninth lens L9 is an example of the negative lens
LG3n.
[0100] Next, the respective lenses that form the fourth lens group
G4 will be described. The twelfth lens L12 is a biconvex lens. The
thirteenth lens L13 is a biconcave lens.
[0101] Next, the respective lenses that form the fifth lens group
G5 will be described. The fourteenth lens L14 is a biconvex lens.
The fifteenth lens L15 is a meniscus lens having a convex surface
facing the image.
[0102] Next, the respective lenses that form the sixth lens group
G6 will be described. The sixteenth lens L16 is a meniscus lens
having a convex surface facing the image. The seventeenth lens L17
is a biconcave lens. The seventeenth lens L17 is an example of the
negative lens GNLn.
[0103] While the zoom lens system according to the third embodiment
is zooming from the wide-angle end toward the telephoto end during
a shooting session, the first lens group G1, the third lens group
G3, the fourth lens group G4, the fifth lens group G5, and the
sixth lens group G6 move toward the object with respect to the
image plane S. On the other hand, the second lens group G2 is fixed
while the zoom lens system is zooming from the wide-angle end
toward the telephoto end during the shooting session. In addition,
as the zoom lens system is zooming, the respective lens groups move
along the optical axis such that the interval between the first
lens group G1 and the second lens group G2 increases, the interval
between the second lens group G2 and the third lens group G3
decreases, the interval between the third lens group G3 and the
fourth lens group G4 decreases, the interval between the fourth
lens group G4 and the fifth lens group G5 increases, and the
interval between the fifth lens group G5 and the sixth lens group
G6 decreases.
[0104] While the zoom lens system according to the third embodiment
is focusing to make a transition from the infinity in-focus state
toward the close-object in-focus state, the fourth lens group G4
moves along the optical axis toward the image plane.
[0105] Note that every lens (image blur compensation lens)
belonging to the second lens group G2 moves perpendicularly to the
optical axis to make optical compensation for image blur. This
image blur compensation lens allows the zoom lens system to make
compensation for the movement of an image point due to the
vibration of the entire system. That is to say, this allows the
zoom lens system to make optical compensation for an image blur
caused by a camera shake or vibrations, for example.
Fourth Embodiment
[0106] FIG. 10 illustrates a zoom lens system according to a fourth
embodiment.
[0107] The zoom lens system includes: a first lens group G1 having
positive power; a second lens group G2 having negative power; a
third lens group G3 having positive power; a fourth lens group G4
having positive power; a fifth lens group G5 having negative power;
a sixth lens group G6 having positive power; and a seventh lens
group G7 having negative power. The first, second, third, fourth,
fifth, sixth, and seventh lens groups G1-G7 are arranged in this
order such that the first lens group G1 is located closer to an
object than any other lens group is and that the seventh lens group
G7 is located closer to an image plane than any other lens group
is.
[0108] The zoom lens system forms an image at a point on the image
plane S.
[0109] The third through seventh lens groups G3-G7 form an
exemplary rear group GR.
[0110] The fifth lens group G5 is an example of the (N-2).sup.th
lens group. The sixth lens group G6 is an example of the
(N-1).sup.th lens group. The seventh lens group G7 is an example of
the N.sup.th lens group.
[0111] The first lens group G1 is made up of: a first lens L1
having negative power; a second lens L2 having positive power; and
a third lens L3 having positive power. The first lens L1, the
second lens L2, and the third lens L3 are arranged in this order
such that the first lens L1 is located closer to the object than
any other member of this first lens group G1 and that the third
lens L3 is located closer to the image plane than any other member
of this first lens group G1. The first lens L1 and the second lens
L2 are bonded together with an adhesive, for example, to form a
bonded lens. In this case, the first lens L1 is an example of the
negative lens G1L1, the second lens L2 is an example of the
positive lens G1L2, and the third lens L3 is an example of the
positive lens G1L3.
[0112] The second lens group G2 is made up of: a fourth lens L4
having negative power; a fifth lens L5 having negative power; and a
sixth lens L6 having positive power. The fourth lens L4, the fifth
lens L5, and the sixth lens L6 are arranged in this order such that
the fourth lens L4 is located closer to the object than any other
member of this second lens group G2 and that the sixth lens L6 is
located closer to the image plane than any other member of this
second lens group G2. The fifth lens L5 and the sixth lens L6 are
bonded together with an adhesive, for example, to form a bonded
lens.
[0113] The third lens group G3 is made up of: an aperture stop A; a
seventh lens L7 having positive power; an eighth lens L8 having
positive power; and a ninth lens L9 having negative power. The
aperture stop A, the seventh lens L7, the eighth lens L8, and the
ninth lens L9 are arranged in this order such that the aperture
stop A is located closer to the object than any other member of
this third lens group G3 and that the ninth lens L9 is located
closer to the image plane than any other member of this third lens
group G3. The eighth lens L8 and the ninth lens L9 are bonded
together with an adhesive, for example, to form a bonded lens.
[0114] The fourth lens group G4 is made up of: a tenth lens L10
having negative power; and an eleventh lens L11 having positive
power. The tenth lens L10 and the eleventh lens L11 are arranged in
this order such that the tenth lens L10 is located closer to the
object than the eleventh lens L11 and that the eleventh lens L11 is
located closer to the image plane than the tenth lens L10.
[0115] The fifth lens group G5 is made up of: a twelfth lens L12
having positive power; and a thirteenth lens L13 having negative
power. The twelfth lens L12 and the thirteenth lens L13 are
arranged in this order such that the twelfth lens L12 is located
closer to the object than the thirteenth lens L13 and that the
thirteenth lens L13 is located closer to the image plane than the
twelfth lens L12. The twelfth lens L12 and the thirteenth lens L13
are bonded together with an adhesive, for example, to form a bonded
lens.
[0116] The sixth lens group G6 is made up of: a fourteenth lens L14
having positive power; and a fifteenth lens L15 having negative
power. The fourteenth lens L14 and the fifteenth lens L15 are
arranged in this order such that the fourteenth lens L14 is located
closer to the object than the fifteenth lens L15 and that the
fifteenth lens L15 is located closer to the image plane than the
fourteenth lens L14. The fourteenth lens L14 and the fifteenth lens
L15 are bonded together with an adhesive, for example, to form a
bonded lens.
[0117] The seventh lens group G7 is made up of: a sixteenth lens
L16 having positive power; and a seventeenth lens L17 having
negative power. The sixteenth lens L16 and the seventeenth lens L17
are arranged in this order such that the sixteenth lens L16 is
located closer to the object than the seventeenth lens L17 and that
the seventeenth lens L17 is located closer to the image plane than
the sixteenth lens L16. The sixteenth lens L16 and the seventeenth
lens L17 are bonded together with an adhesive, for example, to form
a bonded lens.
[0118] The respective lenses will be described.
[0119] First, the respective lenses that form the first lens group
G1 will be described. The first lens L1 is a meniscus lens having a
convex surface facing the object. The second lens L2 is a biconvex
lens. The third lens L3 is a meniscus lens having a convex surface
facing the object.
[0120] Next, the respective lenses that form the second lens group
G2 will be described. The fourth lens L4 is a meniscus lens having
a convex surface facing the object. The fifth lens L5 is a
biconcave lens. The sixth lens L6 is a meniscus lens having a
convex surface facing the object.
[0121] Next, the respective lenses that form the third lens group
G3 will be described. The seventh lens L7 is a biconvex lens. The
eighth lens L8 is a biconvex lens. The ninth lens L9 is a meniscus
lens having a convex surface facing the image. In this case, the
eighth lens L8 is an example of the positive lens LG3p. The ninth
lens L9 is an example of the negative lens LG3n.
[0122] Next, the respective lenses that form the fourth lens group
G4 will be described. The tenth lens L10 is a biconcave lens. The
eleventh lens L11 is a biconvex lens.
[0123] Next, the respective lenses that form the fifth lens group
G5 will be described. The twelfth lens L12 is a biconvex lens. The
thirteenth lens L13 is a biconcave lens.
[0124] Next, the respective lenses that form the sixth lens group
G6 will be described. The fourteenth lens L14 is a biconvex lens.
The fifteenth lens L15 is a meniscus lens having a convex surface
facing the image.
[0125] Next, the respective lenses that form the seventh lens group
G7 will be described. The sixteenth lens L16 is a meniscus lens
having a convex surface facing the image. The seventeenth lens L17
is a biconcave lens. In this case, the seventeenth lens L17 is an
example of the negative lens GNLn.
[0126] While the zoom lens system according to the fourth
embodiment is zooming from the wide-angle end toward the telephoto
end during a shooting session, the first lens group G1, the third
lens group G3, the fourth lens group G4, the fifth lens group G5,
the sixth lens group G6, and the seventh lens group G7 move toward
the object with respect to the image plane S. On the other hand,
the second lens group G2 is fixed while the zoom lens system is
zooming from the wide-angle end toward the telephoto end during the
shooting session. In addition, as the zoom lens system is zooming,
the respective lens groups move along the optical axis such that
the interval between the first lens group G1 and the second lens
group G2 increases, the interval between the second lens group G2
and the third lens group G3 decreases, the interval between the
third lens group G3 and the fourth lens group G4 decreases, the
interval between the fourth lens group G4 and the fifth lens group
G5 increases from the wide-angle end through the middle position
and decreases from the middle position through the telephoto end,
the interval between the fifth lens group G5 and the sixth lens
group G6 increases, and the interval between the sixth lens group
G6 and the seventh lens group G7 decreases.
[0127] While the zoom lens system according to the fourth
embodiment is focusing to make a transition from the infinity
in-focus state toward the close-object in-focus state, the fifth
lens group G5 moves along the optical axis toward the image plane
and the sixth lens group G6 moves along the optical axis toward the
object.
[0128] Note that every lens (image blur compensation lens)
belonging to the second lens group G2 moves perpendicularly to the
optical axis to make optical compensation for image blur. This
image blur compensation lens allows the zoom lens system to make
compensation for the movement of an image point due to the
vibration of the entire system. That is to say, this allows the
zoom lens system to make optical compensation for an image blur
caused by a camera shake or vibrations, for example.
Fifth Embodiment
[0129] FIG. 13 illustrates a zoom lens system according to a fifth
embodiment.
[0130] The zoom lens system includes: a first lens group G1 having
positive power; a second lens group G2 having negative power; a
third lens group G3 having positive power; a fourth lens group G4
having positive power; a fifth lens group G5 having negative power;
a sixth lens group G6 having positive power; and a seventh lens
group G7 having negative power. The first, second, third, fourth,
fifth, sixth, and seventh lens groups G1-G7 are arranged in this
order such that the first lens group G1 is located closer to an
object than any other lens group is and that the seventh lens group
G7 is located closer to an image plane than any other lens group
is.
[0131] The zoom lens system forms an image at a point on the image
plane S.
[0132] The third through seventh lens groups G3-G7 form an
exemplary rear group GR.
[0133] The fifth lens group G5 is an example of the (N-2).sup.th
lens group. The sixth lens group G6 is an example of the
(N-1).sup.th lens group. The seventh lens group G7 is an example of
the N.sup.th lens group.
[0134] The first lens group G1 is made up of: a first lens L1
having negative power; a second lens L2 having positive power; and
a third lens L3 having positive power. The first lens L1, the
second lens L2, and the third lens L3 are arranged in this order
such that the first lens L1 is located closer to the object than
any other member of this first lens group G1 and that the third
lens L3 is located closer to the image plane than any other member
of this first lens group G1. The first lens L1 and the second lens
L2 are bonded together with an adhesive, for example, to form a
bonded lens. In this case, the first lens L1 is an example of the
negative lens G1L1, the second lens L2 is an example of the
positive lens G1L2, and the third lens L3 is an example of the
positive lens G1L3.
[0135] The second lens group G2 is made up of: a fourth lens L4
having negative power; a fifth lens L5 having negative power; and a
sixth lens L6 having positive power. The fourth lens L4, the fifth
lens L5, and the sixth lens L6 are arranged in this order such that
the fourth lens L4 is located closer to the object than any other
member of this second lens group G2 and that the sixth lens L6 is
located closer to the image plane than any other member of this
second lens group G2. The fifth lens L5 and the sixth lens L6 are
bonded together with an adhesive, for example, to form a bonded
lens.
[0136] The third lens group G3 is made up of: an aperture stop A; a
seventh lens L7 having positive power; an eighth lens L8 having
positive power; and a ninth lens L9 having negative power. The
aperture stop A, the seventh lens L7, the eighth lens L8, and the
ninth lens L9 are arranged in this order such that the aperture
stop A is located closer to the object than any other member of
this third lens group G3 and that the ninth lens L9 is located
closer to the image plane than any other member of this third lens
group G3. The eighth lens L8 and the ninth lens L9 are bonded
together with an adhesive, for example, to form a bonded lens.
[0137] The fourth lens group G4 is made up of: a tenth lens L10
having negative power; and an eleventh lens L11 having positive
power. The tenth lens L10 and the eleventh lens L11 are arranged in
this order such that the tenth lens L10 is located closer to the
object than the eleventh lens L11 and that the eleventh lens L11 is
located closer to the image plane than the tenth lens L10.
[0138] The fifth lens group G5 is made up of: a twelfth lens L12
having positive power; a thirteenth lens L13 having negative power,
and a fourteenth lens L14 having negative power. The twelfth lens
L12, the thirteenth lens L13, and the fourteenth lens L14 are
arranged in this order such that the twelfth lens L12 is located
closer to the object than any other member of this fifth lens group
G5 and that the fourteenth lens L14 is located closer to the image
plane than any other member of this fifth lens group G5. The
twelfth lens L12 and the thirteenth lens L13 are bonded together
with an adhesive and the thirteenth lens L13 and the fourteenth
lens L14 are also bonded together with an adhesive, for example, to
form the bonded lens. That is to say, the bonded lens is made up of
three lenses.
[0139] The sixth lens group G6 is made up of: a fifteenth lens L15
having positive power; and a sixteenth lens L16 having negative
power. The fifteenth lens L15 and the sixteenth lens L16 are
arranged in this order such that the fifteenth lens L15 is located
closer to the object than the sixteenth lens L16 and that the
sixteenth lens L16 is located closer to the image plane than the
fifteenth lens L15. The fifteenth lens L15 and the sixteenth lens
L16 are bonded together with an adhesive, for example, to form a
bonded lens.
[0140] The seventh lens group G7 is made up of: a seventeenth lens
L17 having positive power; and an eighteenth lens L18 having
negative power. The seventeenth lens L17 and the eighteenth lens
L18 are arranged in this order such that the seventeenth lens L17
is located closer to the object than the eighteenth lens L18 and
that the eighteenth lens L18 is located closer to the image plane
than the seventeenth lens L17. The seventeenth lens L17 and the
eighteenth lens L18 are bonded together with an adhesive, for
example, to form a bonded lens.
[0141] The respective lenses will be described.
[0142] First, the respective lenses that form the first lens group
G1 will be described. The first lens L1 is a meniscus lens having a
convex surface facing the object. The second lens L2 is a meniscus
lens having a convex surface facing the object. The third lens L3
is a meniscus lens having a convex surface facing the object.
[0143] Next, the respective lenses that form the second lens group
G2 will be described. The fourth lens L4 is a biconcave lens. The
fifth lens L5 is a biconcave lens. The sixth lens L6 is a meniscus
lens having a convex surface facing the object.
[0144] Next, the respective lenses that form the third lens group
G3 will be described. The seventh lens L7 is a biconvex lens. The
eighth lens L8 is a biconvex lens. The ninth lens L9 is a meniscus
lens having a convex surface facing the image. In this case, the
eighth lens L8 is an example of the positive lens LG3p. The ninth
lens L9 is an example of the negative lens LG3n.
[0145] Next, the respective lenses that form the fourth lens group
G4 will be described. The tenth lens L10 is a biconcave lens. The
eleventh lens L11 is a biconvex lens.
[0146] Next, the respective lenses that form the fifth lens group
G5 will be described. The twelfth lens L12 is a biconvex lens. The
thirteenth lens L13 is a biconcave lens. The fourteenth lens L14 is
a meniscus lens having a convex surface facing the object.
[0147] Next, the respective lenses that form the sixth lens group
G6 will be described. The fifteenth lens L15 is a biconvex lens.
The sixteenth lens L16 is a meniscus lens having a convex surface
facing the image.
[0148] Next, the respective lenses that form the seventh lens group
G7 will be described. The seventeenth lens L17 is a meniscus lens
having a convex surface facing the image. The eighteenth lens L18
is a biconcave lens. In this case, the eighteenth lens L18 is an
example of the negative lens GNLn.
[0149] While the zoom lens system according to the fifth embodiment
is zooming from the wide-angle end toward the telephoto end during
a shooting session, the first lens group G1, the third lens group
G3, the fourth lens group G4, the fifth lens group G5, and the
seventh lens group G7 move toward the object with respect to the
image plane S. On the other hand, the second lens group G2 is fixed
while the zoom lens system is zooming from the wide-angle end
toward the telephoto end during the shooting session. Meanwhile,
while the zoom lens system is zooming from the wide-angle end
toward the telephoto end during the shooting session, the sixth
lens group G6 moves to draw a locus that is convex with respect to
the image plane. In addition, as the zoom lens system is zooming,
the respective lens groups move along the optical axis such that
the interval between the first lens group G1 and the second lens
group G2 increases, the interval between the second lens group G2
and the third lens group G3 decreases, the interval between the
third lens group G3 and the fourth lens group G4 decreases from the
wide-angle end through the middle position and increases from the
middle position through the telephoto end, the interval between the
fourth lens group G4 and the fifth lens group G5 increases from the
wide-angle end through the middle position and decreases from the
middle position through the telephoto end, the interval between the
fifth lens group G5 and the sixth lens group G6 increases, and the
interval between the sixth lens group G6 and the seventh lens group
G7 decreases.
[0150] While the zoom lens system according to the fifth embodiment
is focusing to make a transition from the infinity in-focus state
toward the close-object in-focus state, the fifth lens group G5
moves along the optical axis toward the image plane and the sixth
lens group G6 moves along the optical axis toward the object.
[0151] Note that every lens (image blur compensation lens)
belonging to the second lens group G2 moves perpendicularly to the
optical axis to make optical compensation for image blur. This
image blur compensation lens allows the zoom lens system to make
compensation for the movement of an image point due to the
vibration of the entire system. That is to say, this allows the
zoom lens system to make optical compensation for an image blur
caused by a camera shake or vibrations, for example.
Other Embodiments
[0152] The first, second, third, fourth, and fifth embodiments have
been described as exemplary embodiments of the present disclosure.
Note that the embodiments described above are only examples of the
present disclosure and should not be construed as limiting. Rather,
each of these embodiments may be readily modified, replaced,
combined with other embodiments, provided with some additional
components, or partially omitted without departing from the scope
of the present disclosure.
[0153] For example, in the first to fifth embodiments described
above, the zoom lens system is supposed to be used in the entire
zoom range from the wide-angle end through the telephoto end.
However, the zoom lens system does not have to be used in the
entire zoom range. Alternatively, the zoom lens system may also be
used selectively only in an extracted range where optical
performance is ensured according to the desired zoom range. That is
to say, the zoom lens system may also be used as a zoom lens system
with lower zoom power than the zoom lens system to be described for
the first, second, third, fourth, and fifth examples of numerical
values corresponding to the first, second, third, fourth, and fifth
embodiments, respectively. Optionally, the zoom lens system may
also be used selectively as single-focus lens system only at an
extracted focal length where optical performance is ensured
according to the desired zoom position.
[0154] In addition, the number of the lens groups and the number of
the lenses that form each lens group are substantial numbers.
Optionally, a lens having substantially no power may be added to
any of the lens groups described above.
[0155] Furthermore, in the embodiments described above, the image
blur compensation lens is supposed to be every lens in the
(N-2).sup.th lens group GN-2. Alternatively, the image blur
compensation lens may also be some of the lenses that form the
(N-2).sup.th lens group GN-2.
[0156] Also, the zoom lens systems according to the first, second,
third, fourth, and fifth embodiments described above are configured
to compensate for an image blur by shifting the image blur
compensation lens perpendicularly to the optical axis. However,
this is only an example and should not be construed as limiting.
Alternatively, the image blur may also be compensated for as long
as the lens may be shifted to have a component perpendicular to the
optical axis. Thus, if the lens barrel may have a complex
structure, for example, the zoom lens system may also be configured
to compensate for the image blur by pivoting the image blur
compensation lens around a center on the optical axis.
[0157] Furthermore, in the embodiments described above, an example
in which the third lens group G3 includes an aperture stop A
provided closer to the object than any other member of the third
lens group G3 and an example in which the third lens group G3
includes an aperture stop A provided closer to the image plane than
any other member of the third lens group G3 have been described as
examples of the third lens group G3 with an aperture stop A.
However, these are only examples and should not be construed as
limiting. Alternatively, the aperture stop A may also be provided
between any two lenses belonging to the third lens group G3. The
aperture stop A may be provided at any position as long as the
aperture stop A may move along with the third lens group G3 while
the zoom lens system is zooming.
[0158] (Conditions and Advantages)
[0159] Next, conditions for implementing the zoom lens systems
according to the first to fifth embodiments, for example, will be
described. That is to say, a plurality of possible conditions may
be defined for the zoom lens systems according to each of these
five embodiments. In that case, a zoom lens system, of which the
configuration satisfies all of these possible conditions, is most
advantageous. Alternatively, a zoom lens system that achieves its
expected advantages by satisfying any of the individual conditions
to be described below may also be obtained.
[0160] A zoom lens system according to each of the first to fifth
embodiments includes: a first lens group having positive power; a
second lens group having negative power; and a rear group GR
including at least three lens groups each having power. The rear
group GR includes an N.sup.th lens group having negative power, an
(N-1).sup.th lens group having positive power, and an (N-2).sup.th
lens group having negative power. These lens groups are arranged in
this order such that the N.sup.th lens group is located closer to
the image plane than any other one of these lens groups. While the
zoom lens system is zooming, the second lens group does not move
but the interval between each pair of lens groups changes. While
the zoom lens system is focusing to make a transition from an
infinity in-focus state to a close-object in-focus state, at least
the (N-2).sup.th lens group moves along an optical axis.
[0161] The zoom lens system suitably satisfies the condition
expressed by the following Inequality (1):
0.05<BFw/fT<0.15 (1)
where BFw is a back focus at the wide-angle end and fT is a focal
length at the telephoto end.
[0162] The condition expressed by the Inequality (1) defines the
ratio of the back focus at the wide-angle end (i.e., the distance
from a surface, facing the image, of a lens located closest to the
image plane to the image plane) to the focal length at the
telephoto end. Satisfying this condition expressed by the
Inequality (1) enables providing a zoom lens system with the
ability to compensate for various types of aberrations sufficiently
over the entire zoom range and to achieve a high shooting
magnification at the telephoto end.
[0163] Conversely, if the BFw/fT ratio were less than the lower
limit of the condition expressed by the Inequality (1), then it
would be difficult to compensate for various types of aberrations
at the wide-angle end, in particular. On the other hand, if the
BFw/fT ratio were greater than the upper limit of the condition
expressed by the Inequality (1), the exit pupil position would move
toward the object to cause an increase in the size of the lens.
[0164] To enhance the advantage described above, the condition(s)
expressed by one or both of the following Inequalities (1a) and
(1b) is/are suitably satisfied:
0.053<BFw/fT (1a)
BFw/fT<0.14 (1b)
[0165] More suitably, to further enhance the advantage described
above, the condition(s) expressed by one or both of the following
Inequalities (1c) and (1d) is/are satisfied:
0.056<BFw/fT (1c)
BFw/fT<0.12(1d)
[0166] In addition, the zoom lens system has the above-described
configuration including a first lens group having positive power; a
second lens group having negative power; and a rear group GR
including at least three lens groups each having power, and the
second lens group G2 is fixed while the zoom lens system is
zooming. This allows the zoom lens system to have a relatively
small size and compensate for various types of aberrations
sufficiently, even though the zoom lens system uses no aspheric
surface as the optical surface of any lens.
[0167] Also, in the zoom lens system, the first lens group suitably
includes at least three lenses, namely, a negative lens G1L1, a
positive lens G1L2, and a positive lens G1L3, which are arranged in
this order such that the negative lens G1L1 is located closer to
the object than the positive lens G1L2 or the position lens G1L3
and that the positive lens G1L3 is located closer to the image
plane than the negative lens G1L1 or the position lens G1L2. The
zoom lens system suitably satisfies the condition expressed by the
following Inequality (2):
vd1>65 (2)
where vd1 is an abbe number with respect to a d--line of at least
one positive lens selected from the group consisting of a positive
lens G1L2 and a positive lens G1L3.
[0168] The condition expressed by this inequality (2) defines the
abbe number with respect to a d-line of at least one positive lens
selected from the group consisting of a positive lens G1L2 and a
positive lens G1L3. If the abbe number were less than the lower
limit defined by this Inequality (2), then it would be difficult to
compensate for various types of aberrations (such as an axial
chromatic aberration at the telephoto end, among other things).
[0169] To enhance the advantage described above, both the positive
lens G1L2 and the positive lens G1L3 suitably satisfy the condition
expressed by the Inequality (2).
[0170] To further enhance the advantage described above, the
condition expressed by the following Inequality (2a) is suitably
satisfied:
vd1>80 (2a)
[0171] To further enhance the advantage described above, the
condition expressed by the following Inequality (2b) is more
suitably satisfied:
vd1>90 (2b)
[0172] Furthermore, the zoom lens system suitably satisfies the
condition expressed by the following Inequality (3):
0.1<DT/LT<0.25 (3)
where DT is the distance, measured at the telephoto end, along the
optical axis between a surface, located closest to the image plane,
of the (N-2).sup.th lens group and a surface, located closest to
the object, of the (N-1).sup.th lens group, and LT is the total
lens length at the telephoto end.
[0173] As used herein, the "total lens length at the telephoto end"
refers to the distance measured at the telephoto end between a
surface, facing the object, of the first lens L1 and the image
plane S.
[0174] The condition expressed by this Inequality (3) defines the
distance, measured at the telephoto end, along the optical axis
between a surface, located closest to the image plane, of the
(N-2).sup.th lens group and a surface, located closest to the
object, of the (N-1).sup.th lens group. Satisfying the condition
expressed by this Inequality (3) enables increasing the shooting
magnification at the telephoto end.
[0175] Conversely, if the DT/LT ratio were less than the lower
limit defined by this Inequality (3), then the distance (DT),
measured at the telephoto end, along the optical axis between a
surface, located closest to the image plane, of the (N-2).sup.th
lens group and a surface, located closest to the object, of the
(N-1).sup.th lens group would be insufficient, thus making it
difficult to increase the shooting magnification at the telephoto
end. On the other hand, if the DT/LT ratio were greater than the
upper limit defined by this Inequality (3), then the total lens
length (LT) at the telephoto end would be so short as to make it
difficult to compensate for various types of aberrations (e.g., the
field curvature, in particular) at the telephoto end.
[0176] To enhance the advantage described above, the condition(s)
expressed by one or both of the following Inequalities (3a) and
(3b) is/are suitably satisfied:
0.13<DT/LT (3a)
DT/LT<0.23 (3b)
[0177] More suitably, to further enhance the advantage described
above, the condition(s) expressed by one or both of the following
Inequalities (3c) and (3d) is/are satisfied:
0.15<DT/LT (3c)
DT/LT<0.21 (3d)
[0178] Furthermore, in the zoom lens system, the third lens group
G3 suitably includes at least one positive lens LG3p and suitably
satisfies the condition expressed by the following Inequality (4),
for example:
vLG3p>65 (4)
where vLG3p is an abbe number with respect to a d--line of the
positive lens LG3p.
[0179] The condition expressed by this Inequality (4) defines the
abbe number with respect to a d-line of the positive lens LG3p. If
the abbe number were less than the lower limit defined by this
Inequality (4), then it would be difficult to compensate for
various types of aberrations (such as an axial chromatic aberration
over the entire zoom range, among other things).
[0180] To further enhance the advantage described above, the
condition expressed by the following Inequality (4a) is suitably
satisfied:
vLG3p>80 (4a)
[0181] To further enhance the advantage described above, the
condition expressed by the following Inequality (4b) is more
suitably satisfied:
vLG3p>90 (4b)
[0182] Furthermore, the zoom lens system suitably satisfies the
condition expressed by the following inequality (5):
-10<(1-.beta.TGf.times..beta.T.sub.Gf.times..beta.T.sub.Gf).times.(.b-
eta.T.sub.GRR.times..beta.T.sub.GRR)<-5 (5)
where .beta.T.sub.Gf is the lateral magnification at the telephoto
end of the (N-2).sup.th lens group and .beta.T.sub.GRR is the
lateral magnification at the telephoto end of an optical system,
which is located closer to the image plane than the (N-2).sup.th
lens group.
[0183] The condition expressed by this Inequality (5) defines the
lateral magnification at the telephoto end of the (N-2).sup.th lens
group and the lateral magnification at the telephoto end of an
optical system GRR, which is located closer to the image plane than
the (N-2).sup.th lens group. As used herein, the optical system
located closer to the image plane than the (N-2).sup.th lens group
is an optical system consisting of the (N-1).sup.th lens group and
the N.sup.th lens group. More specifically, the optical system
refers to an optical system consisting of the sixth lens group G6
and the seventh lens group G7 according to the first, second,
fourth, and fifth embodiments and an optical system consisting of
the fifth lens group and the sixth lens group according to the
third embodiment.
[0184] If the product calculated by
(1-.beta.T.sub.Gf.times..beta.T.sub.Gf).times.(.beta.T.sub.GRR.times..bet-
a.T.sub.GRR) were less than the lower limit of the condition
expressed by Inequality (5), then the position sensitivity of the
focus lens group would be too high to control the focus lens group
easily. On the other hand, if the product calculated by
(1-.beta.T.sub.Gf.times..beta.T.sub.Gf).times.(.beta.T.sub.GRR.times..bet-
a.T.sub.GRR) were greater than the upper limit of the condition
expressed by Inequality (5), then the magnitude of movement of the
focus lens group would increase too much to reduce the overall size
of the focus lens group easily.
[0185] To enhance the advantage described above, the condition(s)
expressed by one or both of the following Inequalities (5a) and
(5b) is/are suitably satisfied:
--9<(1-.beta.T.sub.Gf.times..beta.T.sub.Gf).times.(.beta.T.sub.GRR.ti-
mes..beta.T.sub.GRR) (5a)
(1-.beta.T.sub.Gf.times..beta.T.sub.Gf).times.(.beta.T.sub.GRR.times..be-
ta.T.sub.GRR)<-5.5 (5b)
[0186] More suitably, to further enhance the advantage described
above, the condition(s) expressed by one or both of the following
Inequalities (5c) and (5d) is/are satisfied:
-8<(1-.beta.T.sub.Gf.times..beta.T.sub.Gf).times.(.beta.T.sub.GRR.tim-
es..beta.T.sub.GRR) (5c)
(1-.beta.T.sub.Gf.times..beta.T.sub.Gf).times.(.beta.T.sub.GRR.times..be-
ta.T.sub.GRR)<-6.0 (5d)
[0187] Furthermore, in the zoom lens system, the second lens group
G2 suitably moves to have a component perpendicular to the optical
axis in order to compensate for the image blur and suitably
satisfies the condition expressed by the following Inequality
(6):
-3.5<(1-.beta.T.sub.G2).times..beta.T.sub.GR<-1.5 (6)
where .beta.T.sub.G2 is the lateral magnification at the telephoto
end of the second lens group and .beta.T.sub.GR is the lateral
magnification at the telephoto end of the rear group GR.
[0188] The condition expressed by this Inequality (6) defines the
image blur compensation sensitivity at the telephoto end of the
second lens group G2 that is an image blur compensation lens
group.
[0189] If the product calculated by
(1-.beta.T.sub.G2).times..beta.T.sub.GR were less than the lower
limit of the condition expressed by this Inequality (6), then the
image blur compensation sensitivity of the image blur compensation
lens group would increase too much to compensate for the image blur
accurately and easily. On the other hand, if the product calculated
by (1-.beta.T.sub.G2).times..beta.T.sub.GR were greater than the
upper limit of the condition expressed by Inequality (6), then the
magnitude of vertical movement of the image blur compensation lens
group would increase so much as to cause a significant increase in
the size of the lens system.
[0190] To enhance the advantage described above, the condition(s)
expressed by one or both of the following Inequalities (6a) and
(6b) is/are suitably satisfied:
-3.2<(1-.beta.T.sub.G2).times..beta.T.sub.GR (6a)
(1-.beta.T.sub.G2).times..beta.T.sub.GR<-1.7 (6b)
[0191] More suitably, to further enhance the advantage described
above, the condition(s) expressed by one or both of the following
Inequalities (6c) and (6d) is/are satisfied:
-3.0<(1-.beta.T.sub.G2).times..beta.T.sub.GR (6c)
(1-.beta.T.sub.G2).times..beta.T.sub.GR<-1.8 (6d)
[0192] Also, in the zoom lens system, each of the lens groups,
which are located at most second closest to the object, in the rear
group GR is suitably a single bonded lens formed by bonding two or
more lenses together.
[0193] This reduces the number of lenses required, thus enabling
facilitating the manufacturing process of the zoom lens system. In
addition, this also reduces the overall weight of the zoom lens
system, thus enabling high-speed focusing.
[0194] Furthermore, the zoom lens system according to each of the
first to fifth embodiments described above includes at least six
lens groups, each having power. While the zoom lens system is
zooming, the interval between each pair of lens groups changes. In
addition, each of three lens groups, respectively located closest,
second closest, and third closest to the image plane, consists of
one or more bonded lenses alone.
[0195] If each of the three lens groups, respectively located
closest, second closest, and third closest to the image plane,
consisted of single lenses alone, then it would be difficult to
properly compensate for the chromatic aberration and a variation in
spherical aberration and field curvature due to zooming. Also, if
each of the three lens groups, respectively located closest, second
closest, and third closest to the image plane, included optical
elements which are spaced from each other, then it would be
difficult to maintain the interval, eccentricity, and tilt of the
lenses, thus often causing a significant difference in quality
between individual products due to a dispersion during the
manufacturing process (i.e., manufacturing error).
[0196] On the other hand, if each of the three lens groups,
respectively located closest, second closest, and third closest to
the image plane, consists of bonded lenses alone, then even a
telephoto zoom lens would still be able to reduce the chances of
causing a decline in imaging performance due to the dispersion
involved with the manufacturing process while properly compensating
for the variations in spherical aberration and field curvature due
to zooming.
[0197] To enhance the advantage described above, each of the three
lens groups, respectively located closest, second closest, and
third closest to the image plane, suitably consists of a single
bonded lens alone or each of the four lens groups, respectively
located closest, second closest, third closest, and fourth closest
to the image plane, suitably consists of one or more bonded lenses
alone.
[0198] More suitably, to further enhance the advantage described
above, each of the four lens groups, which are respectively located
closest, second closest, third closest, and fourth closest to the
image plane, consists of only one bonded lens.
[0199] Furthermore, in the zoom lens system, the second lens group
G2 suitably does not move but is fixed with respect to the image
plane while the zoom lens system is zooming.
[0200] This allows simplifying the structure of a cam mechanism for
driving a lens frame that holds lens groups moving during zooming,
thus enabling reducing the size of the lens system.
[0201] Furthermore, an N.sup.th lens group, which is located closer
to the image plane than any other lens group of the zoom lens
system, suitably includes a negative lens GNLn, and satisfies a
condition expressed by the following Inequality (7):
-0.3<fGNLn/LW<0 (7)
where fGNLn is a focal length of the negative lens GNLn and LW is a
total lens length at the wide-angle end.
[0202] The condition expressed by this Inequality (7) defines the
ratio of the focal length of the negative lens GNLn in the N.sup.th
lens group that is a lens group located closest to the image plane
to the total lens length at the wide-angle end.
[0203] If the fGNLn/LW ratio were less than the lower limit of the
condition expressed by this Inequality (7), then the power of the
negative lens GNLn would increase too much to properly compensate
for the field curvature at the wide-angle end, among other things.
On the other hand, if the fGNLn/LW ratio were greater than the
upper limit of the condition expressed by this Inequality (7), then
the exit pupil position would shift toward the object, thus causing
an increase in the size of the lens system.
[0204] To enhance the advantage described above, the condition(s)
expressed by one or both of the following Inequalities (7a) and
(7b) is/are suitably satisfied:
-0.25<fGNLn/LW (7a)
fGNLn/LW<-0.10 (7b)
[0205] More suitably, to further enhance the advantage described
above, the condition(s) expressed by one or both of the following
Inequalities (7c) and (7d) is/are satisfied:
-0.20<fGNLn/LW (7c)
fGNLn/LW<-0.15 (7d)
[0206] Furthermore, the zoom lens system suitably satisfies the
condition expressed by the following Inequality (8), for
example:
0.3<R_GN.sub.c/fG.sub.N<0.7 (8)
where R_GN.sub.c is the radius of curvature of a bonded face of a
bonded lens that forms part of an N.sup.th lens group located
closer to the image plane than any other lens group of the zoom
lens system, and fG.sub.N is the focal length of the N.sup.th lens
group.
[0207] The condition expressed by this Inequality (8) defines the
ratio of the radius of curvature of a bonded face of a bonded lens
that forms part of an N.sup.th lens group located closer to the
image plane than any other lens group of the zoom lens system to
the focal length of the N.sup.th lens group.
[0208] If the R_GN.sub.c/fG.sub.N ratio were less than the lower
limit of the condition expressed by this Inequality (8), then the
radius of curvature of the bonded face of the bonded lens that
forms part of the N.sup.th lens group would be too small to
manufacture the bonded lens easily. On the other hand, if the
R_GN.sub.c/fG.sub.N ratio were greater than the upper limit of the
condition expressed by Inequality (8), then it would be difficult
to compensate for the chromatic aberration of magnification over
the entire zoom range.
[0209] To enhance the advantage described above, the condition(s)
expressed by one or both of the following Inequalities (8a) and
(8b) is/are suitably satisfied:
0.35<R_GN.sub.c/fG.sub.N (8a)
R_GN.sub.c/fG.sub.N<0.60 (8b)
[0210] More suitably, to further enhance the advantage described
above, the condition(s) expressed by one or both of the following
Inequalities (8c) and (8d) is/are satisfied:
0.40<R_GN.sub.c/fG.sub.N (8c)
R_GN.sub.c/fG.sub.N<0.57 (8d)
[0211] Furthermore, if a lens group located closer to the image
plane than any other lens group of the zoom lens system is called
an N.sup.th lens group, another lens group located adjacent to, and
closer to an object than, the N.sup.th lens group is called an
(N-1).sup.th lens group, and still another lens group located
adjacent to, and closer to the object than, the (N-1.sup.th lens
group is called an (N-2)th lens group, while the zoom lens system
is focusing to make a transition from an infinity in-focus state
toward a close-object in-focus state, at least the (N-2.sup.th lens
group suitably moves along an optical axis, and the zoom lens
system suitably satisfies a condition expressed by the following
Inequality (9):
-1.5<fG.sub.N-1/fG.sub.N<-0.5 (9)
where fG.sub.N-1 is the focal length of the (N-1.sup.th lens group
and fG.sub.N is the focal length of the N.sup.th lens group.
[0212] The condition expressed by this Inequality (9) defines the
ratio of the focal length of the (N-1).sup.th lens group to the
focal length of the N.sup.th lens group.
[0213] If the focal length ratio were less than the lower limit of
the condition expressed by this Inequality (9), then the power of
the N.sup.th lens group would be too high to properly compensate
for the field curvature over the entire zoom range. On the other
hand, if the focal length ratio were greater than the upper limit
of the condition expressed by the Inequality (9), the exit pupil
position would move toward the image plane to cause an increase in
the size of the lens.
[0214] To enhance the advantage described above, the condition(s)
expressed by one or both of the following Inequalities (9a) and
(9b) is/are suitably satisfied:
-1.25<fG.sub.N-1/fG.sub.N (9a)
fG.sub.N-1/fG.sub.N<-0.6 (9b)
[0215] More suitably, to further enhance the advantage described
above, the condition(s) expressed by one or both of the following
Inequalities (9c) and (9d) is/are satisfied:
-1.10<fG.sub.N-1/fG.sub.N (9c)
fG.sub.N-1/fG.sub.N<-0.7 (9d)
[0216] Furthermore, in the zoom lens system, the rear group GR
further includes a third lens group G3 located closer to an object
than any other lens group of the rear group GR. If a negative lens,
having the largest refractive index with respect to a d-line out of
at least one negative lens that forms the third lens group G3, is a
negative lens LG3n, the zoom lens system suitably satisfies the
condition expressed by the following Inequality (10):
nLG3n>1.95 (10)
where nLG3n is a refractive index of the negative lens LG3n with
respect to a d-line.
[0217] The condition expressed by the Inequality (10) defines the
refractive index of the negative lens LG3n with respect to a
d-line. If the refractive index of the negative lens LG3n were less
than the lower limit of the condition expressed by the Inequality
(10), then it would be difficult to compensate for various types of
aberrations, e.g., the spherical aberration at the telephoto end,
among other things.
[0218] To enhance the advantage described above, the condition
expressed by the following Inequality (10a) is suitably
satisfied:
nLG3n>2.00 (10a)
[0219] Furthermore, in the zoom lens system, the rear group GR
further includes a third lens group G3 located closer to an object
than any other lens group of the zoom lens system. If a negative
lens, having the smallest Abbe number with respect to a d-line out
of at least one negative lens that forms the third lens group G3,
is a negative lens LG3n, the zoom lens system suitably satisfies a
condition expressed by the following Inequality (11):
vLG3n<35.0 (11)
where vLG3n is an Abbe number of the negative lens LG3n with
respect to a d-line.
[0220] The condition expressed by the Inequality (11) defines the
Abbe number of the negative lens LG3n with respect to a d-line. If
the Abbe number of the negative lens LG3n were greater than the
upper limit of the condition expressed by the Inequality (11), then
it would be difficult to compensate for various types of
aberrations, e.g., the axial chromatic aberration over the entire
zoom range, among other things.
[0221] To enhance the advantage described above, the condition
expressed by the following Inequality (11a) is suitably
satisfied:
vLG3n<30.0 (11a)
[0222] Furthermore, the zoom lens system suitably satisfies the
condition expressed by the following Inequality (12):
0.2<fT/LT<1.5 (12)
where fT is a focal length at the telephoto end and LT is a total
lens length at the telephoto end.
[0223] As used herein, the total lens length at the telephoto end
refers to the distance, measured at the telephoto end, between a
surface, facing the object, of the first lens L1 and the image
plane S.
[0224] The condition expressed by the Inequality (12) defines the
ratio of the focal length at the telephoto end to the total lens
length at the telephoto end.
[0225] If the fT/LT ratio were less than the lower limit of the
condition expressed by the Inequality (12), then the total lens
length would increase too much with respect to the focal length at
the telephoto end to avoid a significant increase in the size of
the zoom lens system. On the other hand, if the fT/LT ratio were
greater than the upper limit of the condition expressed by the
Inequality (12), then the focal length would increase too much with
respect to the total lens length at the telephoto end, thus making
the zoom lens system small with a short total lens length.
Nevertheless, in that case, the absolute value of the power of each
lens group would be too great to avoid producing various types of
aberrations, e.g., spherical aberration, among other things, in
each lens group. In that case, it would be difficult to compensate
for those various types of aberrations.
[0226] To enhance the advantage described above, the condition(s)
expressed by one or both of the following Inequalities (12a) and
(12b) is/are suitably satisfied:
0.4<fT/LT (12a)
fT/LT<1.4 (12b)
[0227] More suitably, to further enhance the advantage described
above, the condition(s) expressed by one or both of the following
Inequalities (12c) and (12d) is/are satisfied:
0.7<fT/LT (12c)
fT/LT<1.3 (12d)
[0228] Furthermore, the zoom lens system suitably satisfies the
condition expressed by the following Inequality (13):
0.50<fT/LDT<1.85 (13)
where fT is a focal length at a telephoto end, and LDT is a
distance, measured at the telephoto end, along an optical axis from
an object-side surface of a lens located closest to the object to
an image-side surface of a lens located closest to the image
plane.
[0229] The condition expressed by the Inequality (13) defines the
ratio of the focal length at the telephoto end of the zoom lens
system to the distance from an object-side surface of a lens
located closest to the object to an image-side surface of a lens
located closest to the image plane.
[0230] If the fT/LDT ratio were less than the lower limit of the
condition expressed by the Inequality (13), then the distance
measured at the telephoto end from an object-side surface of a lens
located closest to the object to an image-side surface of a lens
located closest to the image plane would increase too much with
respect to the focal length at the telephoto end, thus causing a
significant increase in the size of the zoom lens system. On the
other hand, if the fT/LDT ratio were greater than the upper limit
of the condition expressed by the Inequality (13), then the focal
length would increase too much with respect to the distance
measured at the telephoto end from an object-side surface of a lens
located closest to the object to an image-side surface of a lens
located closest to the image plane, thus reducing the size of the
zoom lens system. Nevertheless, in that case, the absolute value of
the power of each lens group would be too great to avoid producing
various types of aberrations, e.g., spherical aberration, among
other things, in each lens group. In that case, it would be
difficult to compensate for various types of aberrations.
[0231] To enhance the advantage described above, the condition(s)
expressed by one or both of the following Inequalities (13a) and
(13b) is/are suitably satisfied:
0.80<fT/LDT (13a)
fT/LDT<1.80 (13b)
[0232] More suitably, to further enhance the advantage described
above, the condition(s) expressed by one or both of the following
Inequalities (13c) and (13d) is/are satisfied:
1.10<fT/LDT (13c)
fT/LDT<1.77 (13d)
[0233] Furthermore, the zoom lens system suitably satisfies the
condition expressed by the following Inequality (14):
1.0<fT/BFt<6.0 (14)
where fT is the focal length at the telephoto end and BFt is the
back focus distance at the telephoto end.
[0234] The condition expressed by the Inequality (14) defines the
ratio of the focal length at the telephoto end of the zoom lens
system to the back focus (i.e., the distance from the image-side
surface of a lens located closest to the image plane to the image
plane).
[0235] If the fT/BFt ratio were less than the lower limit of the
condition expressed by the Inequality (14), then the back focus
would increase too much with respect to the focal length at the
telephoto end, thus causing a significant increase in the size of
the zoom lens system. On the other hand, if the fT/BFt ratio were
greater than the upper limit of the condition expressed by the
Inequality (14), then the back focus would decrease with respect to
the focal length at the telephoto end, thus reducing the size of
the zoom lens system. Nevertheless, in that case, the power of the
N.sup.th lens group would be too great to easily compensate for
various types of aberrations, e.g., field curvature, among other
things.
[0236] To enhance the advantage described above, the condition(s)
expressed by one or both of the following Inequalities (14a) and
(14b) is/are suitably satisfied:
2.0<fT/BFt (14a)
fT/BFt<5.5 (14b)
[0237] More suitably, to further enhance the advantage described
above, the condition(s) expressed by one or both of the following
Inequalities (14c) and (14d) is/are satisfied:
3.0<fT/BFt (14c)
fT/BFt<5.0 (14d)
[0238] (Schematic configuration for image capture device to which
first embodiment is applied)
[0239] FIG. 16 illustrates a schematic configuration for an image
capture device, to which the zoom lens system of the first
embodiment is applied. Alternatively, the zoom lens system
according to the second, third, fourth, or fifth embodiment is also
applicable to the image capture device.
[0240] The image capture device 100 includes a housing 104, an
image sensor 102, and the zoom lens system 101 according to the
first embodiment. The image capture device 100 may be implemented
as a digital camera, for example.
[0241] A lens barrel 302 holds the respective lens groups and the
aperture stop A that form the zoom lens system 101.
[0242] The image sensor 102 is disposed at the image plane S of the
zoom lens system according to the first embodiment.
[0243] The zoom lens system 101 is configured such that the first
lens group G1, the third lens group G3, the fourth lens group G4,
the fifth lens group G5, the sixth lens group G6, and the seventh
lens group G7 are attached to, or engaged with, a lens frame
included in the lens barrel 302 so as to move while the zoom lens
system 101 is zooming. As used herein, if something is "engaged
with" something else, these two things may be joined together
either by hooking or fitting, whichever is appropriate.
[0244] The zoom lens system 101 is also configured such that the
first lens group G1, the third lens group G3, the fourth lens group
G4, the fifth lens group G5, the sixth lens group G6, and the
seventh lens group G7 are attached to, or engaged with, the lens
frame included in the lens barrel 302 so as to move along with the
lens frame holding the first lens group G1, the third lens group
G3, the fourth lens group G4, the fifth lens group G5, the sixth
lens group G6, and the seventh lens group G7 while the zoom lens
system 101 is zooming.
[0245] The zoom lens system 101 forms an optical image of the
object. The image sensor 102 transforms the optical image of the
object, formed by the zoom lens system 101, into an electrical
image signal. That is to say, the image capture device 100 may
store or output the optical image of the object as the electrical
image signal.
[0246] This provides an image capture device with the ability to
compensate for various types of aberrations sufficiently.
[0247] In the example described above, the zoom lens system
according to the first embodiment is applied to a digital camera.
However, this is only an example and should not be construed as
limiting. Alternatively, the zoom lens system is also applicable to
a surveillance camera, a smartphone, or any of various other types
of image capture devices.
[0248] (Schematic configuration for camera system to which first
embodiment is applied)
[0249] FIG. 17 illustrates a schematic configuration for a camera
system, to which the zoom lens system of the first embodiment is
applied. Alternatively, the zoom lens system according to the
second, third, fourth, or fifth embodiment is also applicable to
the camera system.
[0250] The camera system 200 includes a camera body 201 and an
interchangeable lens unit 300 to be connected removably to the
camera body 201.
[0251] The camera body 201 includes an image sensor 202, a monitor
203, a memory, a camera mount 204, and a viewfinder 205. The image
sensor 202 receives an optical image formed by the zoom lens system
of the interchangeable lens unit 300 and transforms the optical
image into an electrical image signal. The monitor 203 displays the
image signal transformed by the image sensor 202. The memory stores
the image signal.
[0252] The zoom lens system 301 of the interchangeable lens unit
300 is the zoom lens system according to the first embodiment.
[0253] The interchangeable lens unit 300 includes a lens barrel
302. The lens barrel 302 holds the respective lens groups and
aperture stop A of the zoom lens system 301. The lens barrel 302
further includes a lens mount 304 to be connected to the camera
mount 204 of the camera body 201.
[0254] The camera mount 204 and the lens mount 304 are physically
connected together. In addition, the camera mount 204 and the lens
mount 304 also electrically connect together a controller in the
camera body 201 and a controller in the interchangeable lens unit
300. That is to say, the camera mount 204 and the lens mount 304
serve as interfaces that allow themselves to exchange signals with
each other.
[0255] The zoom lens system 301 is configured such that the first
lens group G1, the third lens group G3, the fourth lens group G4,
the fifth lens group G5, the sixth lens group G6, and the seventh
lens group G7 are attached to, or engaged with, a lens frame
included in the lens barrel 302 so as to move while the zoom lens
system 301 is zooming.
[0256] The zoom lens system 301 includes the respective lens groups
held by the lens barrel 302. In addition, the zoom lens system 301
further includes an actuator, a lens frame, and other members to be
controlled by the controller in the interchangeable lens unit 300
such that the fourth lens group G4 may move while the zoom lens
system 301 is focusing.
Examples of Numerical Values
[0257] Next, exemplary sets of specific numerical values that were
actually adopted in the zoom lens systems with the configurations
according to the first, second, third, fourth, and fifth
embodiments will be described. Note that in the tables showing
these exemplary sets of numerical values, the length is expressed
in millimeters (mm), the angle of view is expressed in
degrees)(.degree., r indicates the radius of curvature, d indicates
the surface interval, nd indicates a refractive index with respect
to a d-line, .nu.d (also denoted as "vd") indicates an abbe number
with respect to a d-line, and a surface with an asterisk (*) is an
aspheric surface. The aspheric shape is defined by the following
equation.
Z = h 2 / r 1 + 1 - ( 1 + .kappa. ) .times. ( h / r ) 2 + A n
.times. h n ##EQU00001##
[0258] where Z is the distance from a point on an aspheric surface,
located at a height h measured from the optical axis, to a tangent
plane defined with respect to the vertex of the aspheric surface, h
is the height as measured from the optical axis, r is the radius of
curvature of the vertex, .kappa. is a conic constant, and An is an
n.sup.th order aspheric surface coefficient.
[0259] FIGS. 2, 5, 8, 11, and 14 are longitudinal aberration
diagrams of the zoom lens systems according to the first, second,
third, fourth, and fifth embodiments in the infinity in-focus
state.
[0260] In each longitudinal aberration diagram, portion (a) shows
the longitudinal aberrations at the wide-angle end, portion (b)
shows the longitudinal aberrations at the middle position, and
portion (c) shows the longitudinal aberrations at the telephoto
end. Each of portions (a), (b) and (c) of these longitudinal
aberration diagrams shows spherical aberration (SA (mm)),
astigmatism (AST (mm)), and distortion (DIS (%)) in this order from
left to right. In each spherical aberration diagram, the ordinate
indicates the F number (designated by "F" on the drawings), the
solid curve indicates a characteristic in response to a d-line, the
shorter dashed curve indicates a characteristic in response to an
F-line, and the longer dashed curve indicates a characteristic in
response to a C-line. In each astigmatism diagram, the ordinate
indicates the image height (designated by "H" on the drawings), the
solid curve indicates a characteristic with respect to a sagittal
plane (designated by "s" on the drawings), and the dotted curve
indicates a characteristic with respect to a meridional plane
(designated by "m" on the drawings). Furthermore, in each
distortion diagram, the ordinate indicates the image height
(designated by "H" on the drawings).
[0261] FIGS. 3, 6, 9 12, and 15 are five sets of lateral aberration
diagrams at the telephoto end of the zoom lens systems according to
the first, second, third, fourth, and fifth embodiments,
respectively.
[0262] In each set of lateral aberration diagrams, the upper three
aberration diagrams show characteristics in a basic state where no
image blur compensation is performed at the telephoto end, while
the lower three aberration diagrams show characteristics in an
image blur compensated state at the telephoto end where the image
blur compensation lens group has been shifted to a predetermined
extent perpendicularly to the optical axis.
[0263] In the three lateral aberration diagrams showing the basic
state, the upper diagram shows a characteristic with respect to the
lateral aberration at an image point where the image height is 70%
of the maximum image height, the middle diagram shows a
characteristic with respect to the lateral aberration at an axial
image point, and the lower diagram shows a characteristic with
respect to the lateral aberration at an image point where the image
height is -70% of the maximum image height. Likewise, in the three
lateral aberration diagrams showing the image blur compensated
state, the upper diagram shows a characteristic with respect to the
lateral aberration at the image point where the image height is 70%
of the maximum image height, the middle diagram shows a
characteristic with respect to the lateral aberration at the axial
image point, and the lower diagram shows a characteristic with
respect to the lateral aberration at the image point where the
image height is -70% of the maximum image height. In each lateral
aberration diagram, the abscissa indicates the distance from a
principal ray on the pupil, the solid curve indicates a
characteristic in response to a d-line, the shorter dashed curve
indicates a characteristic in response to an F-line, and the longer
dashed curve indicates a characteristic in response to a
C-line.
[0264] Following are the distances traveled, at the telephoto end,
by the image blur compensation lens groups perpendicularly to the
optical axis when the zoom lens systems according to the respective
examples of numerical values are in the image blur compensated
state.
TABLE-US-00001 First example of numerical values 0.551 mm Second
example of numerical values 0.494 mm Third example of numerical
values 0.549 mm Fourth example of numerical values 0.531 mm Fifth
example of numerical values 0.688 mm
[0265] Note that at the telephoto end with an infinite shooting
distance, the image eccentricity when the zoom lens system has a
tilt angle of 0.3 degrees is equal to the image eccentricity when
the image blur compensation lens group translates by each of these
values perpendicularly to the optical axis.
[0266] As is clear from the lateral aberration diagrams, the
lateral aberration has a good degree of symmetry at the axial image
point in this state. Also, comparing the lateral aberration at the
image point where the image height is +70% of the maximum image
height in the basic state with the lateral aberration at the image
point where the image height is -70% of the maximum image height in
the basic state, it can be seen that the degree of curvature is
small, and the aberration curves have almost the same gradient.
Thus, it can be seen that the eccentric coma aberration and
eccentric astigmatism are both insignificant. These results reveal
that sufficiently good imaging performance is achieved even in the
image blur compensated state. Also, supposing the image blur
compensation angle of the zoom lens system is the same, as the
focal length of the entire zoom lens system becomes shorter, the
degree of translation required for image blur compensation
decreases. This enables making, at any zoom position, image blur
compensation sufficiently with respect to an image blur
compensation angle of about 0.4 degrees without causing a decline
in the imaging performance.
First Example of Numerical Values
[0267] Following is a first exemplary set of numerical values for
the zoom lens system corresponding to the first embodiment shown in
FIG. 1. Specifically, as the first example of numerical values for
the zoom lens system, surface data is shown in Table 1, aspheric
surface data is shown in Table 2, and various types of data in the
infinity in-focus state are shown in Tables 3A-3D:
TABLE-US-00002 TABLE 1 (Surface data) Surface No. r d nd vd Object
surface .infin. 1 149.02930 1.70000 1.90366 31.3 2 90.22010 0.20000
3 94.69470 5.47000 1.49700 81.6 4 -1397.90520 0.15000 5 71.45890
5.86000 1.43700 95.1 6 960.24800 Variable 7 -150.73980 1.10000
1.58913 61.3 8 61.48450 1.53250 9 4030.47630 1.00000 1.59349 67.0
10 30.72580 0.01000 1.56732 42.8 11 30.72580 2.94000 1.84666 23.8
12 59.55230 Variable 13 219.44950 2.62000 1.87071 40.7 14 -69.33020
0.20000 15 36.18720 5.29000 1.49700 81.6 16 -38.66110 0.01000
1.56732 42.8 17 -38.66110 1.00000 2.00100 29.1 18 262.05460 3.00000
19 (aperture) .infin. Variable 20 -127.35720 0.80000 1.84666 23.8
21 226.50870 0.01000 1.56732 42.8 22 226.50870 2.79000 1.80610 33.3
23 -44.71840 Variable 24 342.14550 2.45000 1.86966 20.0 25
-38.63930 0.01000 1.56732 42.8 26 -38.63930 0.60000 1.80610 33.3 27
32.13490 Variable 28 67.74600 5.64000 1.65844 50.9 29 -34.58950
0.01000 1.56732 42.8 30 -34.58950 1.20000 1.92286 20.9 31 -51.34110
Variable 32 -69.64440 3.87000 1.85883 30.0 33 -28.12860 0.01000
1.56732 42.8 34 -28.12860 1.30000 1.80420 46.5 35 110.54230 BF
Image plane .infin.
[0268] (Table 2: Aspheric Surface Data)
[0269] No aspheric surface was existent.
[0270] (Various types of data in infinity in-focus state)
TABLE-US-00003 TABLE 3A (Various types of data) Zoom ratio: 3.95600
Wide-Angle Middle Telephoto Focal length 72.8000 144.7974 287.9970
F number 4.54605 5.43172 5.85441 Angle of view 16.6501 8.3925
4.2458 Image height 21.6330 21.6330 21.6330 Total lens length
165.8343 195.6045 225.2331 BF 22.63464 43.83449 61.26739 d6 3.2665
33.0367 62.7665 d12 35.1758 19.5944 4.0000 d19 9.6870 5.5015 4.7730
d23 4.2909 7.8833 3.9453 d27 11.3199 19.9125 36.7084 d31 28.6871
15.0691 1.0000 Entrance pupil position 51.9122 112.2646 214.9917
Exit pupil position -36.6327 -41.2413 -56.0239 Anterior principal
point 35.2896 10.6193 -204.1591 Posterior principal point 93.0343
50.8070 -62.7639
TABLE-US-00004 TABLE 3B (Data about single lens) Lens Start surface
Focal length 1 1 -256.5229 2 3 178.6630 3 5 176.3143 4 7 -73.9868 5
9 -52.1737 6 11 71.6229 7 13 60.7655 8 15 38.5128 9 17 -33.6010 10
20 -96.1853 11 22 46.5423 12 24 40.0416 13 26 -21.6822 14 28
35.5547 15 30 -118.9628 16 32 52.6743 17 34 -27.7663
TABLE-US-00005 TABLE 3C (Data about zoom lens group) Lens Anterior
Posterior Start Focal configuration principal principal Group
surface length length point point 1 1 137.03189 13.38000 3.35553
7.72474 2 7 -50.90785 6.58250 2.32707 4.56460 3 13 65.82728
12.12000 -3.07149 0.92123 4 20 87.40053 3.60000 3.12033 4.77791 5
24 -48.11615 3.06000 1.88753 3.29028 6 28 50.80927 6.85000 2.37231
5.09281 7 32 -56.00470 5.18000 0.91967 3.32429
TABLE-US-00006 TABLE 3D (Zoom power of zoom lens group) Group Start
surface Wide-angle Middle Telephoto 1 1 0.00000 0.00000 0.00000 2 7
-0.67990 -1.12865 -3.31104 3 13 -1.22321 -1.07775 -0.42039 4 20
0.41670 0.42770 0.54015 5 24 22.52294 7.19296 3.82494 6 28 0.04735
0.15551 0.34357 7 32 1.43729 1.81583 2.12710
Second Example of Numerical Values
[0271] Following is a second exemplary set of numerical values for
the zoom lens system corresponding to the second embodiment shown
in FIG. 4. Specifically, as the second example of numerical values
for the zoom lens system, surface data is shown in Table 4,
aspheric surface data is shown in Table 5, and various types of
data in the infinity in-focus state are shown in Tables 6A-6D:
TABLE-US-00007 TABLE 4 (Surface data) Surface No. r d nd vd Object
surface .infin. 1 188.89800 1.50000 1.90366 31.3 2 92.92790 0.20000
3 99.25230 4.35650 1.59283 68.6 4 -1549.97450 0.15000 5 75.96170
4.48690 1.49700 81.6 6 719.60120 Variable 7 -118.15420 1.10000
1.58913 61.3 8 64.20880 1.06110 9 .infin. 1.00000 1.59349 67.0 10
32.67990 0.01000 1.56732 42.8 11 32.67990 2.37060 1.84666 23.8 12
67.83490 Variable 13 297.10080 2.10440 1.87071 40.7 14 -62.62100
0.20000 15 32.25440 3.92750 1.49700 81.6 16 -44.02090 0.01000
1.56732 42.8 17 -44.02090 1.00000 2.00100 29.1 18 279.78740 3.00000
19 (aperture) .infin. Variable 20 -762.08770 0.80000 1.84666 23.8
21 40.76730 0.01000 1.56732 42.8 22 40.76730 2.83380 1.80610 33.3
23 -59.46970 Variable 24 984.43470 2.47550 1.86966 20.0 25
-29.94080 0.01000 1.56732 42.8 26 -29.94080 0.60000 1.80610 33.3 27
29.02160 Variable 28 59.68570 5.52900 1.65844 50.9 29 -35.96280
0.01000 1.56732 42.8 30 -35.96280 1.20000 1.92286 20.9 31 -51.12000
Variable 32 -66.84880 3.20580 1.85883 30.0 33 -32.02100 0.01000
1.56732 42.8 34 -32.02100 1.30000 1.80420 46.5 35 125.45650 BF
Image plane .infin.
[0272] (Table 5: Aspheric Surface Data)
[0273] No aspheric surface was existent.
[0274] (Various Types of Data in Infinity In-Focus State)
TABLE-US-00008 TABLE 6A (Various types of data) Zoom ratio: 2.76922
Wide-Angle Middle Telephoto Focal length 72.8000 121.1461 201.5992
F number 4.65792 5.48858 5.90664 Angle of view 16.7488 10.0452
6.0901 Image height 21.6300 21.6300 21.6300 Total lens length
145.8293 170.8178 198.1246 BF 22.62963 38.74736 49.82147 d6 3.2085
28.2116 55.5839 d12 26.2876 15.4682 5.1335 d19 9.5232 6.4236 3.4488
d23 3.0829 4.2635 3.0829 d27 13.0064 18.5212 31.2739 d31 23.6300
14.7212 5.3190 Entrance pupil position 42.2852 85.0080 160.7959
Exit pupil position -36.9509 -39.6824 -51.0922 Anterior principal
point 26.1327 19.0265 -40.3478 Posterior principal point 73.0294
49.6717 -3.4747
TABLE-US-00009 TABLE 6B (Data about single lens) Lens Start surface
Focal length 1 1 -203.9236 2 3 157.5015 3 5 170.4849 4 7 -70.4574 5
9 -55.0637 6 11 72.2458 7 13 59.5621 8 15 38.1064 9 17 -37.9396 10
20 -45.6847 11 22 30.3882 12 24 33.4498 13 26 -18.1992 14 28
34.8831 15 30 -136.6196 16 32 68.6444 17 34 -31.6047
TABLE-US-00010 TABLE 6C (Data about zoom lens group) Lens Anterior
Posterior Start Focal configuration principal principal Group
surface length length point point 1 1 137.61105 10.69340 2.80157
6.61027 2 7 -52.19949 5.54170 1.75000 3.68782 3 13 54.12691
10.24190 -1.28523 1.72671 4 20 86.95176 3.64380 2.33390 3.97741 5
24 -40.47070 3.08550 1.75611 3.17606 6 28 46.96361 6.73900 2.21985
4.89195 7 32 -56.47436 4.51580 0.72313 2.81139
TABLE-US-00011 TABLE 6D (Zoom power of zoom lens group) Group Start
surface Wide-angle Middle Telephoto 1 1 0.00000 0.00000 0.00000 2 7
-0.68351 -1.01621 -2.17547 3 13 -0.89307 -0.80600 -0.46131 4 20
0.51437 0.51933 0.57299 5 24 14.71872 9.27977 5.15739 6 28 0.08000
0.12995 0.25831 7 32 1.43089 1.71629 1.91238
Third Example of Numerical Values
[0275] Following is a third exemplary set of numerical values for
the zoom lens system corresponding to the third embodiment shown in
FIG. 7. Specifically, as the third example of numerical values for
the zoom lens system, surface data is shown in Table 7, aspheric
surface data is shown in Table 8, and various types of data in the
infinity in-focus state are shown in Tables 9A-9D:
TABLE-US-00012 TABLE 7 (Surface data) Surface No. r d nd vd Object
surface .infin. 1 301.91110 1.50000 1.90366 31.3 2 136.33490
0.20000 3 148.35010 4.69540 1.49700 81.6 4 -290.77250 0.15000 5
68.89210 5.07390 1.43700 95.1 6 387.89320 Variable 7 -116.24990
1.10000 1.58913 61.3 8 79.16380 1.20100 9 .infin. 1.00000 1.59349
67.0 10 39.44880 0.01000 1.56732 42.8 11 39.44880 2.54580 1.84666
23.8 12 84.32680 Variable 13 163.92360 2.11330 1.87071 40.7 14
-77.23660 0.20000 15 30.65130 4.25270 1.49700 81.6 16 -43.95990
0.01000 1.56732 42.8 17 -43.95990 1.00000 2.00100 29.1 18 122.19240
2.00000 19 (aperture) .infin. 4.48710 20 772.62170 0.80000 1.85344
26.5 21 42.60490 0.01000 1.56732 42.8 22 42.60490 2.84500 1.80610
33.3 23 -58.66410 Variable 24 5192.84510 2.59660 1.86966 20.0 25
-25.81430 0.01000 1.56732 42.8 26 -25.81430 0.60000 1.80610 33.3 27
27.88010 Variable 28 60.95740 6.25970 1.65763 55.4 29 -33.47660
0.01000 1.56732 42.8 30 -33.47660 1.20000 1.88100 20.9 31 -51.12000
Variable 32 -86.96120 3.65300 1.85883 30.0 33 -32.92990 0.01000
1.56732 42.8 34 -32.92990 1.30000 1.80420 46.5 35 99.11010 BF Image
plane .infin.
[0276] (Table 8: Aspheric Surface Data)
[0277] No aspheric surface was existent.
[0278] (Various Types of Data in Infinity In-Focus State)
TABLE-US-00013 TABLE 9A (Various types of data) Zoom ratio: 2.63735
Wide-Angle Middle Telephoto Focal length 72.8006 118.2279 192.0006
F number 4.65781 5.60005 6.05430 Angle of view 17.0656 10.3923
6.3624 Image height 21.6330 21.6330 21.6330 Total lens length
161.6754 182.3301 212.2344 BF 22.63496 41.59907 58.45678 d6 5.6338
26.3132 56.2931 d12 37.7638 21.7946 13.8870 d23 7.0000 4.2009
2.0000 d27 16.4128 19.9047 22.3569 d31 21.3965 17.6841 8.4071
Entrance pupil position 55.1994 85.9895 172.5340 Exit pupil
position -39.9748 -41.5490 -41.8183 Anterior principal point
43.3499 36.1097 -3.0964 Posterior principal point 88.8748 64.1022
20.2338
TABLE-US-00014 TABLE 9B Data about single lens Lens Start surface
Focal length 1 1 -276.2840 2 3 198.3562 3 5 190.7701 4 7 -79.7717 5
9 -66.4689 6 11 85.3305 7 13 60.5429 8 15 37.0377 9 17 -32.1998 10
20 -52.8614 11 22 31.0061 12 24 29.5431 13 26 -16.5454 14 28
33.7465 15 30 -113.7187 16 32 59.8415 17 34 -30.6012
TABLE-US-00015 TABLE 9C Data about zoom lens group Lens Anterior
Posterior Start Focal configuration principal principal Group
surface length length point point 1 1 149.79994 11.61930 3.54041
7.36150 2 7 -61.21198 5.85680 1.71537 3.73187 3 13 39.29411
17.71810 5.30497 8.23917 4 24 -38.09673 3.20660 1.77330 3.25163 5
28 47.91376 7.46970 2.45345 5.37945 6 32 -60.59025 4.96300 1.12754
3.42938
TABLE-US-00016 TABLE 9D Zoom power of zoom lens group Group Start
surface Wide-angle Middle Telephoto 1 1 0.00000 0.00000 0.00000 2 7
-0.79516 -1.08722 -2.32553 3 13 -0.33937 -0.33387 -0.21173 4 24
10.24234 33.51652 10.19968 5 28 0.12569 0.03790 0.12824 6 32
1.39889 1.71188 1.99010
Fourth Example of Numerical Values
[0279] Following is a fourth exemplary set of numerical values for
the zoom lens system corresponding to the fourth embodiment shown
in FIG. 10. Specifically, as the fourth example of numerical values
for the zoom lens system, surface data is shown in Table 10,
aspheric surface data is shown in Table 11, and various types of
data in the infinity in-focus state are shown in Tables
12A-12D:
TABLE-US-00017 TABLE 10 Surface data Surface No. r d nd vd Object
surface .infin. 1 161.03340 2.10000 1.80420 46.5 2 69.08230 7.41770
1.43700 95.1 3 -539.12550 0.20000 4 62.97530 6.57200 1.43700 95.1 5
1792.90660 Variable 6 171.92370 1.00000 1.60311 60.7 7 46.27560
3.70000 8 -56.93060 1.00000 1.43700 95.1 9 36.31660 2.55000 1.84666
23.8 10 56.95310 Variable 11 .infin. 1.00000 (aperture) 12
196.55100 3.50000 1.90043 37.4 13 -59.61910 0.15000 14 37.06690
5.50460 1.43700 95.1 15 -37.06690 0.90000 2.00100 29.1 16
-679.03480 Variable 17 -100.98370 1.00000 1.75520 27.5 18 290.52120
6.07020 19 211.48320 3.00000 1.77250 49.6 20 -49.48270 Variable 21
164.49640 2.50000 1.84666 23.8 22 -56.24940 0.80000 1.80420 46.5 23
30.88460 Variable 24 68.77180 7.18000 1.48749 70.4 25 -25.63210
0.80000 1.84666 23.8 26 -34.13590 Variable 27 -50.79320 3.78690
1.85883 30.0 28 -27.38360 1.30000 1.72916 54.7 29 125.90560 BF
Image plane .infin.
[0280] (Table 11: Aspheric Surface Data)
[0281] No aspheric surface was existent.
[0282] (Various Types of Data in Infinity In-Focus State)
TABLE-US-00018 TABLE 12A Various types of data Zoom ratio: 4.08355
Wide-Angle Middle Telephoto Focal length 71.7497 149.9985 292.9931
F number 4.10186 5.30852 5.85256 Angle of view 16.9066 8.0760
4.1596 Image height 21.6300 21.6300 21.6300 Total lens length
166.5192 199.4960 228.0878 BF 16.72927 39.65796 59.22028 d5 4.0000
36.9777 65.5719 d10 26.7423 14.3995 2.5000 d16 6.7865 2.9348 2.9011
d20 2.0000 6.0636 2.0000 d23 14.8856 20.9786 31.8631 d26 33.3441
16.4524 2.0000 Entrance pupil position 45.8883 106.7616 189.6310
Exit pupil position -43.7691 -46.6244 -54.7389 Anterior principal
point 32.5445 -4.0066 -270.6714 Posterior principal point 94.7695
49.4974 -64.9053
TABLE-US-00019 TABLE 12B Data about single lens Lens Start surface
Focal length 1 1 -151.9870 2 2 140.6484 3 4 149.1812 4 6 -105.3021
5 8 -50.5729 6 9 112.0322 7 12 51.1332 8 14 43.3902 9 15 -39.1953
10 17 -99.1181 11 19 52.1709 12 21 49.7659 13 22 -24.6908 14 24
39.2827 15 25 -127.0047 16 27 64.3711 17 28 -30.7362
TABLE-US-00020 TABLE 12C Data about zoom lens group Lens Anterior
Posterior Start Focal configuration principal principal Group
surface length length point point 1 1 139.06568 16.28970 5.81447
10.95300 2 6 -46.97375 8.25000 3.75629 5.76704 3 11 51.92657
11.05460 -0.31478 3.83558 4 17 94.33140 10.07020 14.37857 17.23857
5 21 -50.26976 3.30000 2.30051 3.78172 6 24 56.88724 7.98000
3.61544 6.19239 7 27 -55.39231 5.08690 0.35802 2.67868
TABLE-US-00021 TABLE 12D Zoom power of zoom lens group Group Start
surface Wide-angle Middle Telephoto 1 1 0.00000 0.00000 0.00000 2 6
-0.59461 -1.02070 -2.69545 3 11 -1.00073 -0.87182 -0.41104 4 17
0.55542 0.56487 0.65919 5 21 9.20022 4.82474 3.29586 6 24 0.12611
0.25278 0.41432 7 27 1.34549 1.75942 2.11258
Fifth Example of Numerical Values
[0283] Following is a fifth exemplary set of numerical values for
the zoom lens system corresponding to the fifth embodiment shown in
FIG. 13. Specifically, as the fifth example of numerical values for
the zoom lens system, surface data is shown in Table 13, aspheric
surface data is shown in Table 14, and various types of data in the
infinity in-focus state are shown in Tables 15A-15D:
TABLE-US-00022 TABLE 13 Surface data Surface No. r d nd vd Object
surface .infin. 1 157.00760 3.00000 1.90043 37.4 2 85.00620 8.81590
1.49700 81.6 3 647.67240 0.28570 4 86.10380 8.55060 1.49700 81.6 5
9477.89080 Variable 6 -335.03150 1.42860 1.48749 70.4 7 70.20500
3.70620 8 -197.39820 1.42860 1.48749 70.4 9 49.32600 3.70220
1.84666 23.8 10 78.60410 Variable 11 .infin. 1.42860 (aperture) 12
208.47360 4.74790 1.91082 35.2 13 -92.99870 0.21430 14 56.14750
7.00100 1.43700 95.1 15 -56.14750 0.90000 2.00100 29.1 16
-1971.72670 Variable 17 -213.28570 1.42860 1.74077 27.8 18
200.86010 9.00000 19 185.61550 3.88620 1.72916 54.7 20 -73.69110
Variable 21 1658.54610 3.00000 1.84666 23.8 22 -61.28980 0.80000
1.72916 54.7 23 134.93630 0.80000 1.87071 40.7 24 43.99310 Variable
25 80.36650 5.00000 1.48749 70.4 26 -38.94890 1.14290 1.84666 23.8
27 -53.81720 Variable 28 -79.30840 3.29590 1.85883 30.0 29
-39.81880 1.20000 1.72916 54.7 30 224.64870 BF Image plane
.infin.
[0284] (Table 14: Aspheric Surface Data)
[0285] No aspheric surface was existent.
[0286] (Various Types of Data in Infinity In-Focus State)
TABLE-US-00023 TABLE 15A Various types of data Zoom ratio: 3.80486
Wide-Angle Middle Telephoto Focal length 102.5002 199.9999 389.9983
F number 4.09951 5.30329 5.87210 Angle of view 12.0879 6.1702
3.1648 Image height 21.6330 21.6330 21.6330 Total lens length
235.4476 262.8697 302.5516 BF 19.91983 57.70275 82.14551 d5 2.0000
29.4223 69.1048 d10 41.3982 17.9428 3.1963 d16 10.9761 7.0589
9.5364 d20 2.7867 8.2796 2.0000 d24 26.3770 36.9782 59.8054 d27
57.2266 30.7220 2.0000 Entrance pupil position 60.0603 93.6001
186.3997 Exit pupil position -70.4735 -78.9594 -107.5737 Anterior
principal point 46.3320 0.9076 -225.3062 Posterior principal point
132.9475 62.8698 -87.4467
TABLE-US-00024 TABLE 15B Data about single lens Lens Start surface
Focal length 1 1 -210.0099 2 2 195.8610 3 4 174.7835 4 6 -118.9264
5 8 -80.8014 6 9 147.8400 7 12 71.1409 8 14 65.4832 9 15 -57.7489
10 17 -139.4374 11 19 72.8025 12 21 69.8659 13 22 -57.7021 14 23
-75.2755 15 25 54.5650 16 26 -172.5941 17 28 89.6567 18 29
-46.2985
TABLE-US-00025 TABLE 15C Data about zoom lens group Lens Anterior
Posterior Start Focal configuration principal principal Group
surface length length point point 1 1 169.18563 20.65220 5.25731
12.31896 2 6 -68.16109 10.26560 4.03070 6.86924 3 11 74.99863
14.29180 -0.41004 4.87634 4 17 130.73034 14.31480 20.20407 24.00056
5 21 -61.53532 4.60000 2.73203 4.81149 6 25 80.17627 6.14290
2.55945 4.65541 7 28 -92.29407 4.49590 0.20492 2.24275
TABLE-US-00026 TABLE 15D Zoom power of zoom lens group Group Start
surface Wide-angle Middle Telephoto 1 1 0.00000 0.00000 0.00000 2 6
-0.78653 -1.15063 -3.48547 3 11 -0.82274 -0.81063 -0.31656 4 17
0.57632 0.56877 0.68692 5 21 31.07664 9.48640 3.93143 6 25 0.04215
0.14239 0.40410 7 28 1.24024 1.64962 1.91445
[0287] (Values Corresponding to Inequalities)
[0288] Values, corresponding to the Inequalities (1) to (14), of
the respective examples of numerical values are shown in the
following Table 16:
TABLE-US-00027 TABLE 16 1.sup.st example 2.sup.nd example 3.sup.rd
example 4.sup.th example 5.sup.th example Numerical values or of
numerical of numerical of numerical of numerical of numerical
conditional values values values values values values BFw 22.63464
22.62963 22.63496 16.72927 19.91983 BFt 61.26739 49.82147 58.45678
59.22028 82.14551 fT 287.9970 201.5992 192.0006 292.9931 389.9983
.nu.d1 Lens L2 81.6 68.6 81.6 95.1 81.6 Lens L3 95.1 81.6 95.1 95.1
81.6 DT 36.7084 31.2739 22.3569 31.8631 59.8054 LT 225.2331
198.1246 212.2344 228.0878 302.5516 LDT 163.9657 148.3031 153.7776
168.8675 220.4061 .nu.LG3p 81.6 81.6 81.6 95.1 95.1 .beta.T.sub.Gf
3.82494 5.15739 10.19968 3.29586 3.93143 .beta.T.sub.GRR 0.73081
0.49399 0.25521 0.87528 0.77363 .beta.T.sub.G2 -3.31104 -2.17547
-2.32553 -2.69545 -3.48547 .beta.T.sub.GR -0.63474 -0.67342
-0.55115 -0.78165 -0.66137 fGNLn -27.76630 -31.60470 -30.60120
-30.73620 -46.29850 LW 165.8343 145.8293 161.6754 166.5192 235.4476
R_GNc -28.12860 -32.02100 -32.92990 -27.38360 -39.81880 fG.sub.N-1
50.80927 46.96361 47.91376 56.88724 80.17627 fGN -56.00470
-56.47436 -60.59025 -55.39231 -92.29407 nLG3n 2.001 2.001 2.001
2.001 2.001 .nu.LG3n 29.1 29.1 29.1 29.1 29.1 Inequality (1) 0.0786
0.1123 0.1179 0.0571 0.0511 Inequality (2) Lens L2 81.6 68.6 81.6
95.1 81.6 Lens L3 95.1 81.6 95.1 95.1 81.6 Inequality (3) 0.1630
0.1578 0.1053 0.1397 0.1977 Inequality (4) 81.6 81.6 81.6 95.1 95.1
Inequality (5) -7.27964 -6.24674 -6.71079 -7.55596 -8.65205
Inequality (6) -2.73639 -2.13843 -1.83287 -2.88855 -2.96656
Inequality (7) -0.16743 -0.21672 -0.18928 -0.18458 -0.19664
Inequality (8) 0.50225 0.56700 0.54349 0.49436 0.43143 Inequality
(9) -0.90723 -0.83159 -0.79078 -1.02699 -0.86870 Inequality (10)
2.001 2.001 2.001 2.001 2.001 Inequality (11) 29.1 29.1 29.1 29.1
29.1 Inequality (12) 1.279 1.018 0.905 1.285 1.289 Inequality (13)
1.756 1.359 1.249 1.735 1.769 Inequality (14) 4.701 4.046 3.284
4.948 4.748
[0289] While the foregoing has described what are considered to be
the best mode and/or other examples, it is understood that various
modifications may be made therein and that the subject matter
disclosed herein may be implemented in various forms and examples,
and that they may be applied in numerous applications, only some of
which have been described herein. It is intended by the following
claims to claim any and all modifications and variations that fall
within the true scope of the present teachings.
[0290] The zoom lens system according to the present disclosure is
applicable to various types of cameras including digital still
cameras, digital cameras, of which the lens is interchangeable,
digital camcorders, cameras for cellphones and smartphones, and
cameras for personal digital assistants (PDAs), surveillance
cameras for surveillance systems, Web cameras, and onboard cameras.
Among other things, the present disclosure is particularly suitably
applicable as a zoom lens system for digital still camera systems,
digital camcorder systems, and other camera systems that require
high image quality.
* * * * *